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Bohrium (Bh)

Bohrium

History

According to the Royal Society of Chemistry, in 1975 a team led by Yuri Oganessian at the Russian Joint Institute for Nuclear Research (JINR) in Dubna, bombarded bismuth with chromium and produced element 107, isotope-261. They published the results of their successful run in 1976 and submitted a discovery claim.

In 1981, a team led by Peter Armbruster and Gottfried Münzenberg at the German nuclear research institute the Geselleschaft für Schwerionenforschung (GSI) bombarded bismuth with chromium and they succeeded in making a single atom of isotope 262. Now followed a period of negotiation to establish who discovered elements 107 first and thereby had the right to name it.

The International Union of Pure and Applied Chemistry (IUPAC) said that the GSI should be awarded the discovery because they had the more credible submission, but that the JINR were probably the first to make it.

Did you know?

  1. Bohrium does not occur naturally and only a few atoms have ever been made. It will probably never be isolated in observable quantities. It was created by the so-called ‘cold fusion’ method. This involved the bombardment of bismuth with atoms of chromium.
  • Atomic Properties
    Atomic number 107
    Atomic weight ( amu ) (262)
    Electronic structure Rn 5f14 6d5 7s2
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Cadmium (Cd)

Cadmium

About

Cadmium was discovered in 1817 by Friedrich Stromeyer at Göttingen, Germany.

Cadmium is a white metallic element. It is readily accessible as it occurs in concentrated ores and is easily extracted by heating the oxide with carbon and distilling the metal. It has an abundance in the earth's crust of 0.11 ppm. Cadmium has been used in applications as diverse as plating, the manufacture of batteries and as a yellow pigment for paint. Cadmium is a poison and is known to cause birth defects and cancer. However, its high toxicity means that its use is now becoming increasingly restricted.

Did you know?

  1. 80% of cadmium currently produced is used in rechargeable nickel-cadmium batteries. However, they are gradually being phased out and replaced with nickel metal hydride batteries.
  2. Other past uses of cadmium included phosphors in cathode ray tube colour TV sets, and yellow, orange and red pigments.
  3. Cadmium absorbs neutrons and so is used in rods in nuclear reactors to control atomic fission.
  • Atomic Properties
    Atomic number 48
    Atomic radius - Goldschmidt ( nm ) 0.152
    Atomic weight ( amu ) 112.41
    Crystal structure Hexagonal close packed
    Electronic structure Kr 4d1O 5s2
    Ionisation potential No. eV
    1 8.99
    2 16.9
    3 37.5
    Natural isotope distribution Mass No. %
    106 1.2
    108 0.9
    110 12.4
    111 12.8
    112 24.0
    113 12.3
    114 28.8
    116 7.6
    Photo-electric work function ( eV ) 4.0
    Thermal neutron absorption cross-section ( Barns ) 2450
    Valences shown 2
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 7.3
    Temperature coefficient @0-100C ( K-1 ) 0.0043
    Superconductivity critical temperature ( K ) 0.517
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) +0.91
  • Mechanical Properties
    Material condition Cast Polycrystalline
    Bulk modulus ( GPa )   51
    Hardness - Mohs 2.0
    Poisson's ratio   0.3
    Tensile modulus ( GPa )   62.6
    Tensile strength ( MPa ) 71
  • Physical Properties
    Boiling point ( C ) 765
    Density @20C ( g cm-3 ) 8.64
    Melting point ( C ) 321
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 31.0
    Latent heat of evaporation ( J g-1 ) 886
    Latent heat of fusion ( J g-1 ) 57
    Specific heat @25C ( J K-1 kg-1 ) 232
    Thermal conductivity @0-100C ( W m-1 K-1 ) 96.9

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Chromium (Cr)

Chromium

History

Chromium is a bright, blue/white metal with excellent corrosion resistance and was discovered in 1780 by N.L. Vanquelin in Paris, France.

It is obtained by the aluminium reduction of Cr2O3, the source of which is chromite, a double oxide of chromium and iron which generally also contains magnesium. It has an abundance within the earth's crust of approximately 100 ppm.

Chromium is soluble in HCl and H2SO4, but not in H3PO4, HNO3 or HClO4 due to the formation of a stable and insoluble oxide layer on its surface; this, along with its hardness, has been used to advantage in the chromium plating of steel which has good corrosion resistance. Chromium is alloyed with nickel in the manufacture of heat resisting alloys, and with iron, or nickel and iron, to produce stainless and heat resistant steels.

Did you know?

  1. Chromium is an essential trace element for humans because it helps us to use glucose. However, it is poisonous in excess. We take in about 1 milligram a day. Foods such as brewer’s yeast, wheat germ and kidney are rich in chromium.
  2. About 90% of all leather is tanned using chrome. However, the waste effluent is toxic so alternatives are being investigated.
  3. Chromium compounds are used as industrial catalysts and pigments (in bright green, yellow, red and orange colours). Rubies get their red colour from chromium, and glass treated with chromium has an emerald green colour.
  • Atomic Properties
    Atomic number 24
    Atomic radius - Goldschmidt ( nm ) 0.128
    Atomic weight ( amu ) 51.996
    Crystal structure Body centred cubic
    Electronic structure Ar 3d5 4s1
    Ionisation potential No. eV
    1 6.77
    2 16.5
    3 31.0
    4 49.1
    5 69.3
    6 90.6
    Natural isotope distribution Mass No. %
    50 4.35
    52 83.79
    53 9.50
    54 2.36
    Photo-electric work function ( eV ) 4.4
    Thermal neutron absorption cross-section ( Barns ) 3.1
    Valences shown 2, 3, 6
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 13.2
    Temperature coefficient @0-100C ( K-1 ) 0.00214
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     160.2
    Hardness - Vickers 130 220
    Poisson's ratio     0.21
    Tensile modulus ( GPa )     279
    Tensile strength ( MPa ) 103 689
  • Physical Properties
    Boiling point ( C ) 2672
    Density @20C ( g cm-3 ) 7.1
    Melting point ( C ) 1857
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 6.5
    Latent heat of evaporation ( J g-1 ) 6580
    Latent heat of fusion ( J g-1 ) 260
    Specific heat @25C ( J K-1 kg-1 ) 518
    Thermal conductivity @0-100C ( W m-1 K-1 ) 94

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Cobalt (Co)

Cobalt

History

Cobalt was discovered in 1735 by G. Brandt in Stockholm, Sweden.

Cobalt is a hard, grey metal which is ferromagnetic. It is usually found in association with nickel in arsenical ores, its abundancy in the Earth's crust being 20 ppm. Cobalt is relatively unreactive, being stable in air and only slowly attacked by dilute acids. It does not combine with hydrogen and nitrogen but it does react with carbon, oxygen and steam at elevated temperatures, producing CoO in the latter cases.

Cobalt salts (primarily cobalt aluminate, known as "Cobalt Blue", or "Thenard's Blue") have been known of and used for centuries to provide a blue colouration to paints and ceramics. Cobalt alloys have good thermal and oxidation resistance, coupled with mechanical strength. The metal is also used in electroplating and its radioactive isotope, 6OCobalt, is used in the treatment of cancer.

Did you know?

  1. Radioactive cobalt-60 is used to treat cancer and, in some countries, to irradiate food to preserve it.
  2. Cobalt is an essential trace element, and forms part of the active site of vitamin B12. The amount we need is very small, and the body contains only about 1 milligram. Cobalt salts can be given to certain animals in small doses to correct mineral deficiencies. In large doses cobalt is carcinogenic.
  3. Cobalt is found in the minerals cobaltite, skutterudite and erythrite. Important ore deposits are found in DR Congo, Canada, Australia, Zambia and Brazil. Most cobalt is formed as a by-product of nickel refining. A huge reserve of several transition metals (including cobalt) can be found in strange nodules on the floors of the deepest oceans. The nodules are manganese minerals that take millions of years to form, and together they contain many tonnes of cobalt.
  • Atomic Properties
    Atomic number 27
    Atomic radius - Goldschmidt ( nm ) 0.125
    Atomic weight ( amu ) 58.9332
    Crystal structure Hexagonal close packed
    Electronic structure Ar 3d7 4s2
    Ionisation potential No. eV
    1 7.86
    2 17.06
    3 33.5
    4 51.3
    5 79.5
    6 102
    Natural isotope distribution Mass No. %
    59 100
    Photo-electric work function ( eV ) 5.0
    Thermal neutron absorption cross-section ( Barns ) 37.5
    Valences shown 2, 3
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 6.34
    Temperature coefficient @0-100C ( K-1 ) 0.0066
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) -1.33
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     181.5
    Hardness - Vickers 170 320
    Poisson's ratio     0.32
    Tensile modulus ( GPa )     211
    Tensile strength ( MPa ) 760 1135
    Yield strength ( MPa ) 345-485
  • Physical Properties
    Boiling point ( C ) 2870
    Density @20C ( g cm-3 ) 8.9
    Melting point ( C ) 1495
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 12.5
    Latent heat of evaporation ( J g-1 ) 6490
    Latent heat of fusion ( J g-1 ) 263
    Specific heat @25C ( J K-1 kg-1 ) 456
    Thermal conductivity @0-100C ( W m-1 K-1 ) 100

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Copernicium (Cn)

Copernicum

History

The first atoms of element 112 were announced by Sigurd Hofmann and produced at the Gesellschaft fur Schwerionenforschung (GSI) at Darmstadt, Germany, in 1996. Isotope-277 had been produced by bombarding lead for two weeks with zinc travelling at 30,000 km per second. Isotope-277 had a half-life of 0.24 milliseconds.

Since then, other isotopes of copernicium have been made. Isotope-285 was observed as part of the decay sequence of flerovium (element 114) produced at the Joint Institute for Nuclear Research (JINR) at Dubna, Russia, as was isotope-284 which was observed as part of the decay sequence of livermorium (element 116).

Did you know?

  1. It is named after the astronomer Nicolaus Copernicus.
  2. The most stable known isotope, copernicium-285, has a half-life of approximately 29 seconds.
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Copper (Cu)

Copper

History

Copper was known to ancient civilisations. Copper is a reddish coloured metal which is malleable and ductile. It has excellent thermal and electrical conductivities and good corrosion resistance. It is found in sulphide ores and as carbonate, arsenide and chloride (abundance in the Earth's crust is 50 ppm). Extraction of the metal involves roasting the ore to produce the oxide, followed by reduction and purification by electrolysis. The element is inert to non-oxidising acids but reacts with oxidising agents. In air, it will weather to produce the characteristic green patina of the carbonate. Copper will combine with oxygen on heating to produce CuO at red heat, and Cu2O at elevated temperatures.

Pure copper has an electrical conductivity second only to that of silver and hence its main application is in the electrical industry. Copper is also the basis of many important alloys (e.g. brass, bronze and aluminium bronze) and has been traditionally considered to be one of the coinage metals, along with silver and gold, but being more common, is the least valued. It is one of the first metals ever to have been worked by man and is thought to have been mined for more than 5000 years.

Did you know?

  1. Most copper is used in electrical equipment such as wiring and motors. This is because it conducts both heat and electricity very well, and can be drawn into wires. It also has uses in construction (for example roofing and plumbing), and industrial machinery (such as heat exchangers).
  2. Copper sulfate is used widely as an agricultural poison and as an algicide in water purification.
  3. Copper is an essential element. An adult human needs around 1.2 milligrams of copper a day, to help enzymes transfer energy in cells. Excess copper is toxic. Genetic diseases, such as Wilson’s disease and Menkes’ disease, can affect the body’s ability to use copper properly.
  • Atomic Properties
    Atomic number 29
    Atomic radius - Goldschmidt ( nm ) 0.128
    Atomic weight ( amu ) 63.546
    Crystal structure Face centred cubic
    Electronic structure Ar 3d1O 4s1
    Ionisation potential No. eV
    1 7.73
    2 20.29
    3 36.8
    4 55.2
    5 79.9
    6 103
    Natural isotope distribution Mass No. %
    63 69.2
    65 30.8
    Photo-electric work function ( eV ) 4.5
    Thermal neutron absorption cross-section ( Barns ) 3.8
    Valences shown 1, 2
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 1.69
    Temperature coefficient @0-100C ( K-1 ) 0.0043
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) +0.76
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     137.8
    Hardness - Vickers 49 87
    Izod toughness ( J m-1 ) 58 68
    Poisson's ratio     0.343
    Tensile modulus ( GPa )     129.8
    Tensile strength ( MPa ) 224 314
    Yield strength ( MPa ) 54 270
  • Physical Properties
    Boiling point ( C ) 2567
    Density @20C ( g cm-3 ) 8.96
    Melting point ( C ) 1083
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 17.0
    Latent heat of evaporation ( J g-1 ) 4796
    Latent heat of fusion ( J g-1 ) 205
    Specific heat @25C ( J K-1 kg-1 ) 385
    Thermal conductivity @0-100C ( W m-1 K-1 ) 401

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Darmstadtium (Ds)

Darmstadtium

History

According to the Royal Society of Chemistry, there are 15 known isotopes of darmstadtium, isotopes 267-281, and the heaviest is the longest-lived, with a half-life of 4 minutes.

There were several attempts to make element 110 at the Joint Institute for Nuclear Research (JINR) at Dubna in Russia, and at the German Geselleschaft für Schwerionenforschung (GSI) at Darmstadt, but all were unsuccessful. Then Albert Ghiorso and his team at the Lawrence Berkeley National Laboratory (LBNL), California, obtained isotope 267 by bombarding bismuth with cobalt, but they could not confirm their findings.

In 1994, a team headed by Yuri Oganessian and Vladimir Utyonkov at the JINR made isotope-273 by bombarding plutonium with sulfur. The same year, a team headed by Peter Armbruster and Gottfried Munzenberg at the GSI bombarded lead with nickel and synthesised isotope 269. The latter group’s evidence was deemed more reliable and confirmed by others around the world, so they were allowed to name element 110.

Did you know?

  1. A man-made element of which only a few atoms have ever been created. It that is formed by fusing nickel and lead atoms in a heavy ion accelerator.
  • Atomic Properties
    Atomic number 110
    Atomic weight ( amu ) 281
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Dubnium (Db)

Dubnium

History

According to the Royal Society of Chemistry, in 1968, a team led by Georgy Flerov at the Russian Joint Institute for Nuclear Research (JINR) bombarded americium with neon and made an isotope of element 105. In 1970, a team led by Albert Ghiorso at the American Lawrence Berkeley Laboratory (LBL) bombarded californium with neon and obtained isotope 261. They disputed the claim of the JINR people. The two groups gave it different names. The Russians called it neilsbohrium, while the Americans called it hahnium, both being derived from the names of prominent nuclear scientists.

Eventually, the International Union of Pure and Applied Chemistry (IUPAC) decided it should be called dubnium.

Did you know?

  1. A highly radioactive metal, of which only a few atoms have ever been made.
  2. Dubnium does not occur naturally. It is a transuranium element created by bombarding californium-249 with nitrogen-15 nuclei.
  • Atomic Properties
    Atomic number 105
    Atomic weight ( amu ) (262)
    Electronic structure Rn 5p14 6d3 7s2
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Gold (Au)

Gold

History

This metal has been known since prehistoric times.

Gold is a soft metal with a characteristic yellow colour. It is the most malleable and ductile of any element. It is unaffected by air, water, alkalis and acids, with the exception of "aqua regia", HNO3/HCl. The fact that it is chemically unreactive means that it is often found in its natural state. It is a good thermal and electrical conductor and has excellent reflective properties to both light and infrared. It has an abundance in the earth's crust of 0.0011 ppm.

Did you know?

  1. Most of the metal is retained for use as bullion reserves, but some is used within the electronics and jewellery industries, where it is frequently alloyed with other elements to improve the mechanical properties of the metal (e.g. copper and silver).
  2. Gold nanoparticles are increasingly being used as industrial catalysts. Vinyl acetate, which is used to make PVA (for glue, paint and resin), is made using a gold catalyst.
  3. Gold can be beaten into very thin sheets (gold leaf) to be used in art, for decoration and as architectural ornament. Electroplating can be used to cover another metal with a very thin layer of gold. This is used in gears for watches, artificial limb joints, cheap jewellery and electrical connectors. It is ideal for protecting electrical copper components because it conducts electricity well and does not corrode (which would break the contact). Thin gold wires are used inside computer chips to produce circuits.
  • Atomic Properties
    Atomic number 79
    Atomic radius - Goldschmidt ( nm ) 0.144
    Atomic weight ( amu ) 196.9665
    Crystal structure Face centred cubic
    Electronic structure Xe 4f14 5d1O 6s1
    Ionisation potential No. eV
    1 9.22
    2 20.5
    Natural isotope distribution Mass No. %
    197 100
    Photo-electric work function ( eV ) 4.8
    Thermal neutron absorption cross-section ( Barns ) 98.8
    Valences shown 1,3
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 2.20
    Temperature coefficient @0-100C ( K-1 ) 0.0040
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) +0.74
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     171
    Hardness - Vickers 20-30 60
    Poisson's ratio     0.42
    Tensile modulus ( GPa )     78.5
    Tensile strength ( MPa ) 130 220
    Yield strength ( MPa )   205
  • Physical Properties
    Boiling point ( C ) 3080
    Density @20C ( g cm-3 ) 19.30
    Melting point ( C ) 1064.4
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 14.1
    Latent heat of evaporation ( J g-1 ) 1738
    Latent heat of fusion ( J g-1 ) 64.9
    Specific heat @25C ( J K-1 kg-1 ) 129
    Thermal conductivity @0-100C ( W m-1 K-1 ) 318

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Hafnium (Hf)

Hafnium

History

Hafnium was discovered in 1923 by D. Coster and G.C. von Hevesey in Copenhagen, Denmark.

Hafnium is a silvery coloured, ductile metal which is found in all minerals containing zirconium. The chemistries of the two metals are similar which makes them difficult to separate, and the properties of each are greatly affected by the presence of the other as an impurity. Both zirconium and hafnium are extracted as the pure metal by reducing the tetrahalide with magnesium, the whole process being carried out under argon as both metals readily combine with other gases (e.g. nitrogen). The abundance of hafnium in the earth's crust is 5.3 ppm.

Hafnium will resist corrosion in air due to the formation of an oxide film, although powdered hafnium will burn in air. It is unaffected by alkalis and acids, with the exception of HF. Hafnium can be used to control recrystallisation of tungsten filaments but its main application is as control rod material in nuclear reactors due to its ability to absorb neutrons. The ability of hafnium to absorb neutrons means that it can sometimes be an annoying impurity in zirconium metal which is used for nuclear engineering.

Did you know?

  1. Hafnium is a good absorber of neutrons and is used to make control rods, such as those found in nuclear submarines. It also has a very high melting point and because of this is used in plasma welding torches.
  2. Hafnium has been successfully alloyed with several metals including iron, titanium and niobium.
  3. Hafnium oxide is used as an electrical insulator in microchips, while hafnium catalysts have been used in polymerisation reactions.
  • Atomic Properties
    Atomic number 72
    Atomic radius - Goldschmidt ( nm ) 0.159
    Atomic weight ( amu ) 178.49
    Crystal structure Hexagonal close packed
    Electronic structure Xe 4f14 5d2 6s2
    Ionisation potential No. eV
    1 7.0
    2 14.9
    3 23.3
    4 33.3
    Natural isotope distribution Mass No. %
    174 0.2
    176 5.2
    177 18.5
    178 27.1
    179 13.8
    180 35.2
    Photo-electric work function ( eV ) 3.9
    Thermal neutron absorption cross-section ( Barns ) 103
    Valences shown 4
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 32.2
    Temperature coefficient @0-100C ( K-1 ) 0.0044
    Superconductivity critical temperature ( K ) 0.128
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     109
    Hardness - Vickers 150-180
    Poisson's ratio     0.26
    Tensile modulus ( GPa )     141
    Tensile strength ( MPa ) 445 745
    Yield strength ( MPa ) 240 365
  • Physical Properties
    Boiling point ( C ) 4602
    Density @20C ( g cm-3 ) 13.1
    Melting point ( C ) 2227
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 6.0
    Latent heat of evaporation ( J g-1 ) 3700
    Latent heat of fusion ( J g-1 ) 122
    Specific heat @25C ( J K-1 kg-1 ) 146
    Thermal conductivity @0-100C ( W m-1 K-1 ) 23.0

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Hassium (Hs)

Hassium

History

According to the Royal Society of Chemistry, there are 15 known isotopes of hassium with mass numbers 263 to 277, with isotope-276 having the longest half-life of 1.1 hour. The first attempt to synthesize element 108 took place in 1978 at Russia’s Joint Institute for Nuclear Research (JINR) in Dubna, where a team headed by Yuri Oganessian and Vladimir Utyonkov bombarded radium with calcium and got isotope 270. In 1983, they obtained other isotopes: by bombarding bismuth with manganese they got isotope 263, by bombarding californium with neon they got isotope 270, and by bombarding lead with iron they got isotope 264.

In 1984, at Germany’s Gesellschaft für Schwerionenforschung (GSI) in Darmstadt, a team headed by Peter Armbruster and Gottfried Münzenberg bombarded lead with iron and synthesised isotope 265. Their data which was considered more reliable than that from JINR and so they were allowed to name the element which they did, basing it on Hesse, the state in which the GSI is located.

Did you know?

  1. Hassium does not occur naturally and it will probably never be isolated in observable quantities. It is created by bombarding lead with iron atoms.
  • Atomic Properties
    Atomic number 108
    Atomic weight ( amu ) 265
    Electronic structure Rn 5f14 6d6 7s2
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Iridium (Ir)

Iridium

History

Iridium was discovered in 1803 in London by S. Tennant.

Iridium is a rare, precious metal which is hard, brittle and has a low ductility, which makes it a difficult material to work. In appearance, it is a lustrous, silvery metal. It has an abundance in the earth's crust of approximately 3x10 6 ppm.

As might be expected from its position in the periodic table, iridium is stable to air and water and is not attacked by any acids, including "aqua regia" (this acid is used to separate iridium from the other platinum group metals). However, fused NaOH will attack iridium.

Did you know?

  1. It is extremely corrosion resistant and is used as an alloying agent with metals such as gold and osmium to produce alloys which are extremely hard and have good corrosion resistance.
  2. Iridium is also used in spark plugs, and its radioactive isotope, €92Ir is a medium energy gamma emitter used for industrial radiography.
  3. A very thin layer of iridium exists in the Earth’s crust. It is thought that this was caused by a large meteor or asteroid hitting the Earth. Meteors and asteroids contain higher levels of iridium than the Earth’s crust. The impact would have caused a huge dust cloud depositing the iridium all over the world. Some scientists think that this could be the same meteor or asteroid impact that wiped out the dinosaurs.
  • Atomic Properties
    Atomic number 77
    Atomic radius - Goldschmidt ( nm ) 0.135
    Atomic weight ( amu ) 192.22
    Crystal structure Face centred cubic
    Electronic structure Xe 4f14 5d7 6s2
    Ionisation potential No. eV
    1 9.1
    Natural isotope distribution Mass No. %
    191 37.3
    193 62.7
    Photo-electric work function ( eV ) 4.6
    Thermal neutron absorption cross-section ( Barns ) 425
    Valences shown 3, 4
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 5.1
    Temperature coefficient @0-100C ( K-1 ) 0.0045
    Superconductivity critical temperature ( K ) 0.11
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) +0.65
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     371
    Hardness - Vickers 200-300 650
    Poisson's ratio     0.26
    Tensile modulus ( GPa )     528
    Tensile strength ( MPa ) 550-1100 1200
  • Physical Properties
    Boiling point ( C ) 4130
    Density @20C ( g cm-3 ) 22.4
    Melting point ( C ) 2410
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 6.8
    Latent heat of evaporation ( J g-1 ) 3186
    Latent heat of fusion ( J g-1 ) 135
    Specific heat @25C ( J K-1 kg-1 ) 133
    Thermal conductivity @0-100C ( W m-1 K-1 ) 147

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Iron (Fe)

Iron

History

Iron was known and used by ancient civilisations.

It is one of the most abundant metals (41000 ppm in the earth's crust), iron is probably one of the most important, being used on the largest scale of any metal. Its production in the blast furnace is well documented. When pure, iron is a lustrous white metal which is soft and very workable. However, it is reactive and easily forms a coating of hydrated oxide on its surface in the presence of moist air. This is non-coherent and flakes easily to reveal fresh surfaces for attack. Iron is soluble in dilute acids, where Fe(II) is produced in solution; more oxidising acids produce Fe(III) solutions and strongly oxidising agents (e.g. dichromate or concentrated nitric acid) produce a passive form of the metal, probably as a result of the formation of a coherent surface film of oxide.

Depending upon the temperature, pure iron can exist in three forms, namely alpha-, gamma- and delta-iron; alpha iron is a polymorphic form of iron which is stable below 906C; it has a body centred cubic lattice (bcc) and is magnetic up to 768C. Gamma iron is a polymorphic form of iron which is stable between 906C and 1403C; it has a face centred cubic lattice (fcc) and is nonmagnetic (n.b. its range of stability is reduced by the presence of carbon, manganese and nickel and it is the basis of the austenite solid solutions). Delta iron is the polymorphic form of iron which is stable between 1403C and the melting point; it has the same lattice structure as alpha iron.

Did you know?

  1. Iron is an essential element for all forms of life and is non-toxic. The average human contains about 4 grams of iron. A lot of this is in haemoglobin, in the blood. Haemoglobin carries oxygen from our lungs to the cells, where it is needed for tissue respiration. Humans need 10–18 milligrams of iron each day. A lack of iron will cause anaemia to develop. Foods such as liver, kidney, molasses, brewer’s yeast, cocoa and liquorice contain a lot of iron.
  2. Iron is the fourth most abundant element, by mass, in the Earth’s crust. The core of the Earth is thought to be largely composed of iron with nickel and sulfur. The most common iron-containing ore is haematite, but iron is found widely distributed in other minerals such as magnetite and taconite.
  3. Iron is the basis for many types of steel, the properties being achieved by the alloying of iron with carbon, nickel, chromium and other elements in varying proportions which results in materials with vastly differing mechanical and physical properties.
  • Atomic Properties
    Atomic number 26
    Atomic radius - Goldschmidt ( nm ) 0.128
    Atomic weight ( amu ) 55.847
    Crystal structure Body centred cubic
    Electronic structure Ar 3d6 4s2
    Ionisation potential No. eV
    1 7.87
    2 16.18
    3 30.65
    4 54.8
    5 75.0
    6 99
    Natural isotope distribution Mass No. %
    54 5.8
    56 91.8
    57 2.1
    58 0.3
    Photo-electric work function ( eV ) 4.4
    Thermal neutron absorption cross-section ( Barns ) 2.56
    Valences shown 2, 3, 4, 6
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 10.1
    Temperature coefficient @0-100C ( K-1 ) 0.0065
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) +1.98
  • Mechanical Properties
    Material condition Polycrystalline
    Bulk modulus ( GPa ) 169.8
    Hardness - Mohs 4.0-5.0
    Izod toughness ( J m-1 ) 8-16
    Poisson's ratio 0.293
    Tensile modulus ( GPa ) 211.4
    Tensile strength ( MPa ) 180-210
    Yield strength ( MPa ) 120-150
  • Physical Properties
    Boiling point ( C ) 2750
    Density @20C ( g cm-3 ) 7.87
    Melting point ( C ) 1535
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 12.1
    Latent heat of evaporation ( J g-1 ) 6095
    Latent heat of fusion ( J g-1 ) 272
    Specific heat @25C ( J K-1 kg-1 ) 444
    Thermal conductivity @0-100C ( W m-1 K-1 ) 80.4

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Manganese (Mn)

Manganese

History

Manganese was discovered in 1774 by J.G. Grahn in Stockholm, Sweden.

Manganese is abundant in the earth's crust (950 ppm) and its principle ore is pyrolusite, a crude form of the dioxide. It is obtained by reduction with aluminium or in a blast furnace. Pure manganese is a hard, brittle, silvery coloured, metallic element which exists in three polymorphic forms (alpha, beta and gamma) and has a complicated crystal structure. It resembles iron in being moderately reactive and dissolving in cold, dilute non-oxidising acids. When exposed to air, manganese forms an extremely stable oxide coating which is not easily reduced. Pure manganese is ferromagnetic after processing.

Did you know?

  1. Manganese is not used as the basis of alloys but it is a common constituent of alloys based on other systems, its addition resulting in a significant improvement in the physical and mechanical properties of the resulting alloys. For example, it is present in all steels and cast iron, the concentration being increased for special grades of material; it is also added to certain grades of brass and bronze as well as some nickel and aluminium base alloys.
  2. The average human body contains about 12 milligrams of manganese. We take in about 4 milligrams each day from such foods as nuts, bran, wholegrain cereals, tea and parsley. Without it, bones grow spongier and break more easily. It is also essential for utilisation of vitamin B1.
  3. The main mining areas for manganese are in China, Africa, Australia and Gabon. The metal is obtained by reducing the oxide with sodium, magnesium or aluminium, or by the electrolysis of manganese sulfate. Manganese nodules have been found on the floor of the oceans. These nodules contain about 24% manganese, along with smaller amounts of many other elements.
  • Atomic Properties
    Atomic number 25
    Atomic radius - Goldschmidt ( nm ) 0.112
    Atomic weight ( amu ) 54.938
    Crystal structure Body centred cubic
    Electronic structure Ar 3d5 4s2
    Ionisation potential No. eV
    1 7.43
    2 15.64
    3 33.67
    4 51.2
    5 72.4
    6 95
    Natural isotope distribution Mass No. %
    55 100
    Photo-electric work function ( eV ) 3.8
    Thermal neutron absorption cross-section ( Barns ) 13.3
    Valences shown 1, 2, 3, 4, 6, 7
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 160
  • Mechanical Properties
    Material condition Polycrystalline
    Bulk modulus ( GPa ) 118
    Hardness - Mohs 5.0
    Poisson's ratio 0.24
    Tensile modulus ( GPa ) 191
  • Physical Properties
    Boiling point ( C ) 1962
    Density @20C ( g cm-3 ) 7.4
    Melting point ( C ) 1244
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 23.0
    Latent heat of evaporation ( J g-1 ) 4207
    Latent heat of fusion ( J g-1 ) 267
    Specific heat @25C ( J K-1 kg-1 ) 477
    Thermal conductivity @0-100C ( W m-1 K-1 ) 7.81

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Meitnerium (Mt)

Meitnerium

History

According to the Royal Society of Chemistry, there are 7 isotopes of meitnerium with mass numbers in the range 266 to 279. The longest lived is isotope 278 with a half-life of 8 seconds. Meitnerium was first made in 1982 at the German nuclear research facility, the Gesellschaft für Schwerionenforschung (GSI), by a group headed by Peter Armbruster and Gottfried Münzenberg. They bombarded a target of bismuth with accelerated iron ions. After a week, a single atom of element 109, isotope 266, was detected. This underwent radioactive decay after 5 milliseconds.

Did you know?

  1. Fewer than 10 atoms of meitnerium have ever been made, and it will probably never be isolated in observable quantities. It is made by bombarding bismuth with iron atoms.
  • Atomic Properties
    Atomic number 109
    Atomic weight ( amu ) 266
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Mercury (Hg)

Mercury

History

Mercury was known to ancient civilisations. The chemical symbol, Hg, comes from the Latin word "hydragyrum" which means liquid silver, it being the most common liquid metal at room temperature. As a liquid, the metal is extremely mobile and dense and as a solid, it is ductile and malleable (mercury has a melting point of -39C). It is a readily accessible element as it occurs in concentrated ores, mercury (II) oxide being decomposed by heating alone at around 500C (i.e. with no reducing agent), at which temperature mercury distils out.

The element and many of its compounds are extremely toxic and, as mercury has a relatively high vapour pressure at room temperature, mercury surfaces should always be kept covered to reduce vapourisation.

One application with which many people will be familiar is the mercury barometer, an instrument used for measuring the pressure of the atmosphere in terms of the height of a column of mercury which exerts an equal pressure.

Did you know?

  1. Mercury has fascinated people for millennia, as a heavy liquid metal. However, because of its toxicity, many uses of mercury are being phased out or are under review. It is now mainly used in the chemical industry as catalysts. It is also used in some electrical switches and rectifiers.
  2. Previously its major use was in the manufacture of sodium hydroxide and chlorine by electrolysis of brine. These plants will all be phased out by 2020. It was also commonly used in batteries, fluorescent lights, felt production, thermometers and barometers. Again, these uses have been phased out.
  3. Mercury has no known biological role, but is present in every living thing and widespread in the environment. Every mouthful of food we eat contains a little mercury. Our daily intake is less than 0.01 milligrams (about 0.3 grams in a lifetime), and this we can cope with easily. However, in much higher doses it is toxic and one form of mercury – methylmercury – is particularly dangerous. It can accumulate in the flesh of fish and be eaten by people, making them ill.
  • Atomic Properties
    Atomic number 80
    Atomic radius - Goldschmidt ( nm ) 0.155
    Atomic weight ( amu ) 200.59
    Crystal structure Rhombohedral
    Electronic structure Xe 4f14 5d1O 6s2
    Ionisation potential No. eV
    1 10.44
    2 18.76
    3 34.2
    Natural isotope distribution Mass No. %
    196 0.2
    198 10.1
    199 16.9
    200 23.1
    201 13.2
    202 29.7
    204 6.8
    Photo-electric work function ( eV ) 4.49
    Thermal neutron absorption cross-section ( Barns ) 375
    Valences shown 1, 2
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 95.9
    Temperature coefficient @0-100C ( K-1 ) 0.001
    Superconductivity critical temperature ( K ) 4.15
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) 0.045
  • Mechanical Properties
    Material condition Liquid
    Bulk modulus ( GPa ) 25
  • Physical Properties
    Boiling point ( C ) 357
    Density @20C ( g cm-3 ) 13.6
    Melting point ( C ) -38.87
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 61
    Latent heat of evaporation ( J g-1 ) 300
    Latent heat of fusion ( J g-1 ) 11.5
    Specific heat @25C ( J K-1 kg-1 ) 138
    Thermal conductivity @0-100C ( W m-1 K-1 ) 8.65
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Molybdenum (Mo)

Molybdenum

History

Molybdenum was discovered in 1871 by P.J. Hjelm in Uppsala, Sweden.

Molybdenum is a lustrous, silvery coloured metal which has an abundance of 1.5 ppm in the earth's crust. In many instances, it shows a resemblance to tungsten with which it tends to be paired in the transition series in the periodic table, but their chemistries tend to show more distinct differences than might be expected.

Molybdenum has a high melting point and applications for the pure metal take advantage of this; for example, the pure material is used as resistance heating elements in furnaces, as filament supports in electric lamps, and as electrodes for mercury vapour lamps. Molybdenum is used as an alloying agent in certain grades of steel, Permalloys and Stellites (a series of alloys which contain varying proportions of Cr, Co, W and Mo, are very hard and are used in cutting tools and to protect surfaces subject to heavy wear).

Did you know?

  1. Although it is toxic in anything other than small quantities, molybdenum is an essential element for animals and plants. There are about 50 different enzymes used by plants and animals that contain molybdenum. One of these is nitrogenase, found in nitrogen-fixing bacteria that make nitrogen from the air available to plants. Leguminous plants have root nodules that contain these nitrogen-fixing bacteria.
  2. Molybdenum has a very high melting point so it is produced and is often sold as a grey powder. Many molybdenum items are formed by compressing the powder at a very high pressure.
  3. Molybdenum disulfide is used as a lubricant additive. Other uses for molybdenum include catalysts for the petroleum industry, inks for circuit boards, pigments and electrodes.
  • Atomic Properties
    Atomic number 42
    Atomic radius - Goldschmidt ( nm ) 0.140
    Atomic weight ( amu ) 95.94
    Crystal structure Body centred cubic
    Electronic structure Kr 4d5 5s1
    Ionisation potential No. eV
    1 7.10
    2 16.15
    3 27.2
    4 46.4
    5 61.2
    6 68
    Natural isotope distribution Mass No. %
    92 14.8
    94 9.3
    95 15.9
    96 16.7
    97 9.6
    98 24.1
    100 9.6
    Photo-electric work function ( eV ) 4.2
    Thermal neutron absorption cross-section ( Barns ) 2.65
    Valences shown 2, 3, 4, 5, 6
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 5.7
    Temperature coefficient @0-100C ( K-1 ) 0.00435
    Superconductivity critical temperature ( K ) 0.915
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) +1.45
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     261.2
    Hardness - Vickers 200 250
    Poisson's ratio   0.293
    Tensile modulus ( GPa )     324.8
    Tensile strength ( MPa ) 485-550 620-690
    Yield strength ( MPa ) 415-450 550
  • Physical Properties
    Boiling point ( C ) 4612
    Density @20C ( g cm-3 ) 10.22
    Melting point ( C ) 2617
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 5.1
    Latent heat of evaporation ( J g-1 ) 6153
    Latent heat of fusion ( J g-1 ) 290
    Specific heat @25C ( J K-1 kg-1 ) 251
    Thermal conductivity @0-100C ( W m-1 K-1 ) 138

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Nickel (Ni)

Nickel

History

Nickel was discovered by A.F. Cronstedt in 1751 in Stockholm, Sweden.

Nickel is a silver-white metal which occurs mainly in the sulphide and arsenic ores. It is extracted by roasting to NiO and then reducing using carbon. Pure nickel is manufactured by the Mond process, in which impure nickel is reacted with carbon monoxide (CO) to produce Ni(CO)4, which is then decomposed at 200C to yield 99.99% Ni. Nickel has an abundance of 80 ppm in the earth's crust.

Pure nickel is malleable and ductile, and is resistant to corrosion in air or water, and hence is used as a protective coating. It is readily soluble in dilute acids, but is unaffected by alkalis. Applications for nickel include its use as a constituent of various alloy types; for example, Nichrome (an alloy used for resistance heating elements), Monel (corrosion resistant material), Permalloy (an alloy with high magnetic permeability at low field strength and low hysteresis loss), stainless steel, cupro-nickel, nickel silver, etc. It is also used as a protective coating and within food and chemical handling plants.

Did you know?

  1. Nickel is classed as a carcinogen and is also an allergen to some individuals. It is found in many dietary constituents and, as such, is difficult to avoid.
  2. Nickel is used in batteries, including rechargeable nickel-cadmium batteries and nickel-metal hydride batteries used in hybrid vehicles.
  3. Nickel has a long history of being used in coins. The US five-cent piece (known as a ‘nickel’) is 25% nickel and 75% copper.
  • Atomic Properties
    Atomic number 28
    Atomic radius - Goldschmidt ( nm ) 0.125
    Atomic weight ( amu ) 58.69
    Crystal structure Face centred cubic
    Electronic structure Ar 3d8 4s2
    Ionisation potential No. eV
    1 7.63
    2 18.2
    3 35.2
    4 54.9
    5 75.5
    6 108
    Natural isotope distribution Mass No. %
    58 68.27
    60 26.10
    61 1.13
    62 3.59
    64 0.91
    Photo-electric work function ( eV ) 4.9
    Thermal neutron absorption cross-section ( Barns ) 4.54
    Valences shown 0, 1, 2, 3
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 6.9
    Temperature coefficient @0-100C ( K-1 ) 0.0068
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) -1.48
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     177.3
    Hardness - Brinell 100 190
    Izod toughness ( J m-1 ) 160 160
    Poisson's ratio     0.312
    Tensile modulus ( GPa )     199.5
    Tensile strength ( MPa ) 400 660
    Yield strength ( MPa ) 150 480
  • Physical Properties
    Boiling point ( C ) 2732
    Density @20C ( g cm-3 ) 8.9
    Melting point ( C ) 1453
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 13.3
    Latent heat of evaporation ( J g-1 ) 6378
    Latent heat of fusion ( J g-1 ) 292
    Specific heat @25C ( J K-1 kg-1 ) 444
    Thermal conductivity @0-100C ( W m-1 K-1 ) 90.9

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Niobium (Nb)

Niobium

History

Niobium was discovered in 1801 by C. Hatchett in London, England.

Niobium is a silver coloured metal which is generally found in conjunction with tantalum, the two elements being separated by fractional crystallisation of their respective fluoro-complexes. It has an abundance of 20 ppm in the earth's crust. As a pure metal, is very reactive and forms an extremely stable oxide when exposed to air which enhances its corrosion resistance. Niobium will react with a variety of non-metals at elevated temperatures.

Niobium and its alloys have high melting points and are, therefore, used in high temperature engineering products (for use at temperatures in excess of 1200C). Niobium also finds applications in atomic reactors due to its corrosion resistance and, when combined with either tin (Nb3Sn) or zirconium, it has a high degree of superconductivity.

Did you know?

  1. Niobium is used in alloys including stainless steel. It improves the strength of the alloys, particularly at low temperatures. Alloys containing niobium are used in jet engines and rockets, beams and girders for buildings and oil rigs, and oil and gas pipelines.
  2. This element also has superconducting properties. It is used in superconducting magnets for particle accelerators, MRI scanners and NMR equipment.
  3. Niobium oxide compounds are added to glass to increase the refractive index, which allows corrective glasses to be made with thinner lenses.
  • Atomic Properties
    Atomic number 41
    Atomic radius - Goldschmidt ( nm ) 0.147
    Atomic weight ( amu ) 92.9064
    Crystal structure Body centred cubic
    Electronic structure Kr 4d4 5s1
    Ionisation potential No. eV
    1 6.88
    2 14.3
    3 25.0
    4 38.3
    5 50.5
    6 103
    Natural isotope distribution Mass No. %
    93 100
    Photo-electric work function ( eV ) 4.3
    Thermal neutron absorption cross-section ( Barns ) 1.15
    Valences shown 2, 3, 4, 5
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 16
    Temperature coefficient @0-100C ( K-1 ) 0.0026
    Superconductivity critical temperature ( K ) 9.25
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     170.3
    Hardness - Vickers 115 160
    Izod toughness ( J m-1 ) 10-120
    Poisson's ratio     0.397
    Tensile modulus ( GPa )     104.9
    Tensile strength ( MPa ) 330 585
    Yield strength ( MPa ) 240 550
  • Physical Properties
    Boiling point ( C ) 3380
    Density @20C ( g cm-3 ) 6.1
    Melting point ( C ) 1890
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 7.2
    Latent heat of evaporation ( J g-1 ) 7360
    Latent heat of fusion ( J g-1 ) 290
    Specific heat @25C ( J K-1 kg-1 ) 268
    Thermal conductivity @0-100C ( W m-1 K-1 ) 53.7
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Osmium (Os)

Osmium

History

Osmium was discovered in 1803 by Smithson Tennant in London, England.

Osmium is a member of the platinum group of metals and is commonly found in conjunction with these elements (abundancy is 1 x 10 4 ppm in the earth's crust). The mixed metals can be extracted from the ore with aqua regia, followed by treatment of the soluble and insoluble portions in various ways. Osmium is found in both portions and is removed as the volatile tetroxide, which can then be reduced. Pure osmium is silver in colour and is the densest of all metals.

Applications for osmium include its use as an alloying constituent with other group metals, the resultant alloys being extremely hard (e.g. osmiridium, a naturally occuring alloy of osmium and iridium which is extremely hard and is used for the tips of pen nibs).

Did you know?

  1. Osmium has only a few uses. It is used to produce very hard alloys for fountain pen tips, instrument pivots, needles and electrical contacts.
  2. It has a pungent smell, due to the formation of osmium tetroxide.
  3. Osmium can also be used as a powerful catalyst in gas reactions.
  • Atomic Properties
    Atomic number 76
    Atomic radius - Goldschmidt ( nm ) 0.135
    Atomic weight ( amu ) 190.2
    Crystal structure Hexagonal close packed
    Electronic structure Xe 4f14 5d6 6s2
    Ionisation potential No. eV
    1 8.7
    2 16
    Natural isotope distribution Mass No. %
    184 0.02
    186 1.58
    187 1.6
    188 13.3
    189 16.1
    190 26.4
    192 41.0
    Photo-electric work function ( eV ) 4.8
    Thermal neutron absorption cross-section ( Barns ) 15.3
    Valences shown 0, 1, 2, 3, 4, 5, 6, 7, 8
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 8.8
    Temperature coefficient @0-100C ( K-1 ) 0.0041
    Superconductivity critical temperature ( K ) 0.66
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     373
    Hardness - Vickers 300-350 670-1000
    Poisson's ratio     0.25
    Tensile modulus ( GPa )     559
  • Physical Properties
    Boiling point ( C ) 5027
    Density @20C ( g cm-3 ) 22.5
    Melting point ( C ) 3045
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 4.57
    Latent heat of evaporation ( J g-1 ) 3305
    Latent heat of fusion ( J g-1 ) 154
    Specific heat @25C ( J K-1 kg-1 ) 131
    Thermal conductivity @0-100C ( W m-1 K-1 ) 87.6

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Palladium (Pd)

Palladium

History

Discovered in 1803 by W.H. Woollaston in London, England.

Palladium is a member of the platinum group of metals. It is silvery white in colour, is malleable and ductile, and is one of the most reactive in the group. It has an abundance of 6x10 6 in the earth's crust.

Palladium has good corrosion resistance but is soluble in oxidising acids and fused alkalis. It readily absorbs hydrogen gas (up to 900 times its own volume), but its main use is as a catalyst for hydrogenation.

Did you know?

  1. Most palladium is used in catalytic converters for cars. It is also used in jewellery and some dental fillings and crowns. White gold is an alloy of gold that has been decolourised by alloying with another metal, sometimes palladium.
  2. It is used in the electronics industry in ceramic capacitors, found in laptop computers and mobile phones. These consist of layers of palladium sandwiched between layers of ceramic.
  3. Finely divided palladium is a good catalyst and is used for hydrogenation and dehydrogenation reactions. Hydrogen easily diffuses through heated palladium and this provides a way of separating and purifying the gas.
  • Atomic Properties
    Atomic number 46
    Atomic radius - Goldschmidt ( nm ) 0.137
    Atomic weight ( amu ) 106.42
    Crystal structure Face centred cubic
    Electronic structure Kr 4d1O
    Ionisation potential No. eV
    1 8.3
    2 19.4
    3 32.9
    Natural isotope distribution Mass No. %
    102 1.0
    104 11.0
    105 22.2
    106 27.3
    108 26.7
    110 11.8
    Photo-electric work function ( eV ) 5.0
    Thermal neutron absorption cross-section ( Barns ) 6.0
    Valences shown 2, 3, 4
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 10.8
    Temperature coefficient @0-100C ( K-1 ) 0.0042
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) -0.57
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     187
    Hardness - Vickers 40 100
    Poisson's ratio     0.39
    Tensile modulus ( GPa )     121
    Tensile strength ( MPa ) 140-195 325
    Yield strength ( MPa ) 34.5 205
  • Physical Properties
    Boiling point ( C ) 3140
    Density @20C ( g cm-3 ) 12.0
    Melting point ( C ) 1554
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 11.0
    Latent heat of evaporation ( J g-1 ) 3398
    Latent heat of fusion ( J g-1 ) 157
    Specific heat @25C ( J K-1 kg-1 ) 244
    Thermal conductivity @0-100C ( W m-1 K-1 ) 71.8

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Platinum (Pt)

Platinum

History

Platinum was known to native South Americans before the arrival of Columbus and was introduced into Europe around 1750.

Platinum is a member of the platinum group metals and is lustrous, malleable and ductile; it has an abundance of approximately 0.001 ppm in the earth's crust. Of the group of six metals (Pt, Pd, Os, Ir, Rh and Ru), it is the most important. It is unaffected by oxygen and water and is only soluble in aqua regia or fused alkalis.

Applications for platinum are many and varied; for example, it is used to make weights and measures standards, it is used in the electronics industry for electrical contacts which might be subject to high temperatures, and it is used to manufacture electrodes which might be subject to chemical attack.

Did you know?

  1. Platinum is used extensively for jewellery. Its main use, however, is in catalytic converters for cars, trucks and buses. This accounts for about 50% of demand each year. Platinum is very effective at converting emissions from the vehicle’s engine into less harmful waste products.
  2. Platinum is used in the chemicals industry as a catalyst for the production of nitric acid, silicone and benzene. It is also used as a catalyst to improve the efficiency of fuel cells.
  3. Most commercially produced platinum comes from South Africa, from the mineral cooperite (platinum sulfide). Some platinum is prepared as a by-product of copper and nickel refining.
education image

It’s official: Goodfellow wire is now part of Saturn

When the Cassini-Huygens spacecraft hurtled toward the surface of Saturn this month for its final act, it took with it a sensor that had a direct connection to Goodfellow.


Read More Here >>
  • Atomic Properties
    Atomic number 78
    Atomic radius - Goldschmidt ( nm ) 0.138
    Atomic weight ( amu ) 195.08
    Crystal structure Face centred cubic
    Electronic structure Xe 4f14 5d9 6s1
    Ionisation potential No. eV
    1 9.0
    2 18.6
    Natural isotope distribution Mass No. %
    190 0.01
    192 0.79
    194 32.90
    195 33.80
    196 25.30
    198 7.20
    Photo-electric work function ( eV ) 5.3
    Thermal neutron absorption cross-section ( Barns ) 9.0
    Valences shown 1, 2, 3, 4
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 10.58
    Temperature coefficient @0-100C ( K-1 ) 0.00392
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     276
    Hardness - Vickers 40 100
    Poisson's ratio     0.39
    Tensile modulus ( GPa )     170
    Tensile strength ( MPa ) 125-150 200-300
    Yield strength ( MPa ) 14-35 185
  • Physical Properties
    Boiling point ( C ) 3827
    Density @20C ( g cm-3 ) 21.45
    Melting point ( C ) 1772
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 9.0
    Latent heat of evaporation ( J g-1 ) 2405
    Latent heat of fusion ( J g-1 ) 101
    Specific heat @25C ( J K-1 kg-1 ) 133
    Thermal conductivity @0-100C ( W m-1 K-1 ) 71.6

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Rhenium (Re)

Rhenium

History

Rhenium was discovered in 1925 by W. Noddack, O. Berg and Ida Tacke in Berlin, Germany.

Rhenium was named after "Rhenus", the Latin name for the Rhine. It is a rare element (abundance 4 x 10 4 ppm in the earth's crust) and does not occur in quantity in any ore. It is found in ores which contain molybdenum from which it can be readily recovered. The metal is obtained by hydrogen reduction of the potassium perrhenate salt, obtained by precipitation of the perrhenate ion (ReO4) - from an oxidised solution.

Rhenium is a silvery coloured metal which resists corrosion and oxidation but slowly tarnishes in moist air. It is soluble in nitric and sulphuric acids.

Did you know?

  1. Rhenium is among the rarest metals on Earth. It does not occur uncombined in nature or as a compound in a mineable mineral species. It is, however, widely spread throughout the Earth’s crust to the extent of about 0.001 parts per million. Commercial production of rhenium is by extraction from the flue dusts of molybdenum smelters.
  2. Rhenium is used as an additive to tungsten- and molybdenum-based alloys to give useful properties. These alloys are used for oven filaments and x-ray machines. It is also used as an electrical contact material as it resists wear and withstands arc corrosion.
  3. Rhenium catalysts are extremely resistant to poisoning (deactivation) and are used for the hydrogenation of fine chemicals. Some rhenium is used in nickel alloys to make single-crystal turbine blades.
  • Atomic Properties
    Atomic number 75
    Atomic radius - Goldschmidt ( nm ) 0.138
    Atomic weight ( amu ) 186.207
    Crystal structure Hexagonal close packed
    Electronic structure Xe 4f14 5d5 6s2
    Ionisation potential No. eV
    1 7.87
    2 16.6
    Natural isotope distribution Mass No. %
    185 37.4
    187 62.6
    Photo-electric work function ( eV ) 5.0
    Thermal neutron absorption cross-section ( Barns ) 85
    Valences shown -1, 1, 2, 3, 4, 5, 6, 7
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 18.7
    Temperature coefficient @0-100C ( K-1 ) 0.0045
    Superconductivity critical temperature ( K ) 1.70
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     334
    Hardness - Vickers 280 700
    Poisson's ratio     0.26
    Tensile modulus ( GPa )     466
    Tensile strength ( MPa ) 1125 2225
    Yield strength ( MPa ) 315 2150
  • Physical Properties
    Boiling point ( C ) 5627
    Density @20C ( g cm-3 ) 21.0
    Melting point ( C ) 3180
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 6.6
    Latent heat of evaporation ( J g-1 ) 3824
    Latent heat of fusion ( J g-1 ) 179.9
    Specific heat @25C ( J K-1 kg-1 ) 138
    Thermal conductivity @0-100C ( W m-1 K-1 ) 48.0

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Rhodium (Rh)

Rhodium

History

Rhodium was discovered in 1803 by W.H. Woolaston in London.

One of the rarest metals on earth (abundance of 2 x 10 4 ppm), rhodium does not appear naturally, tending to be found with other platinum group metals. It is a hard, lustrous, silvery coloured metal which is stable in air. Rhodium is inert to all acids but is attacked by fused alkalis.

The metal has high thermal and electrical conductivities and is alloyed with platinum to form the positive wire of a Pt/Rh - Pt thermocouple. Other applications of the material include its use as a plating material (to provide a hard and bright surface which is resistant to oxidation), as a catalyst and also as an alloying element, where it improves the hardness of the resulting alloy.

Did you know?

  1. The major use of rhodium is in catalytic converters for cars (80%). It reduces nitrogen oxides in exhaust gases.
  2. Rhodium is also used as catalysts in the chemical industry, for making nitric acid, acetic acid and hydrogenation reactions.
  3. It is used to coat optic fibres and optical mirrors, and for crucibles, thermocouple elements and headlight reflectors. It is used as an electrical contact material as it has a low electrical resistance and is highly resistant to corrosion.
  • Atomic Properties
    Atomic number 45
    Atomic radius - Goldschmidt ( nm ) 0.134
    Atomic weight ( amu ) 102.9055
    Crystal structure Face centred cubic
    Electronic structure Kr 4d8 5s1
    Ionisation potential No. eV
    1 7.46
    2 18.1
    3 31.1
    Natural isotope distribution Mass No. %
    103 100
    Photo-electric work function ( eV ) 4.6
    Thermal neutron absorption cross-section ( Barns ) 150
    Valences shown 2, 3, 4, 5, 6
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 4.7
    Temperature coefficient @0-100C ( K-1 ) 0.0044
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) +0.70
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     276
    Hardness - Vickers 120 300
    Poisson's ratio     0.26
    Tensile modulus ( GPa )     379
    Tensile strength ( MPa ) 690-760 1380-2070
    Yield strength ( MPa ) 69-275
  • Physical Properties
    Boiling point ( C ) 3727
    Density @20C ( g cm-3 ) 12.4
    Melting point ( C ) 1965
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 8.5
    Latent heat of evaporation ( J g-1 ) 4800
    Latent heat of fusion ( J g-1 ) 210
    Specific heat @25C ( J K-1 kg-1 ) 244
    Thermal conductivity @0-100C ( W m-1 K-1 ) 150

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Roentgenium (Rg)

Roentgenium

History

According to the Royal Society of Chemistry, there are seven known isotopes of the element: 272, 274 and 278-282. The longest lived is isotope 281 which has a half-life of 22.8 seconds. In 1986, physicists at the Russian Joint Institute for Nuclear Research (JINR), bombarded bismuth with nickel hoping to make element 111, but they failed to detect any atoms of element 111.

In 1994, a team led by Peter Armbruster and Gottfred Munzenberg at the German Geselleschaft für Schwerionenforschung (GSI), were successful when they bombarded bismuth with nickel and they obtained few atoms of isotope 272. It had a half-life of 1.5 milliseconds.

Did you know?

  1. A man-made element of which only a few atoms have ever been created. It is made by fusing nickel and bismuth atoms in a heavy ion accelerator.
  • Atomic Properties
    Atomic number 111
    Atomic weight ( amu ) 280
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Ruthenium (Ru)

Ruthenium

History

Ruthenium was initially discovered in 1808 by J.A. Sniadecki at the University of Vilnius, Lithuania and then again by G.W. Osnann in 1828 at the University of Tartu, Russia.

Ruthenium is a rare member of the platinum group of metals (abundance 0.001 ppm in the earth's crust). It is a lustrous, silvery coloured metal which is unaffected by air, water and acids, but is soluble in fused alkalis. Extraction of the metal is achieved by several techniques; for example, extraction of the mixed platinum group metals by dissolution in aqua regia, followed by treatment of the various soluble and insoluble fractions.

Did you know?

  1. Many new uses are emerging for ruthenium. Most is used in the electronics industry for chip resistors and electrical contacts. Ruthenium oxide is used in the chemical industry to coat the anodes of electrochemical cells for chlorine production. Ruthenium is also used in catalysts for ammonia and acetic acid production. Ruthenium compounds can be used in solar cells, which turn light energy into electrical energy.
  2. Applications of the metal are limited; as a pure metal, ruthenium is extremely hard and brittle and, consequently, difficult to machine. It is relatively unreactive, and is used as an alloying element with platinum and palladium to produce alloys which have improved wear resistance, and with titanium to improve the material's corrosion resistance. In all cases, the ruthenium addition has to be less than 15%, otherwise the resultant alloy is too hard to work.
  • Atomic Properties
    Atomic number 44
    Atomic radius - Goldschmidt ( nm ) 0.134
    Atomic weight ( amu ) 101.07
    Crystal structure Hexagonal close packed
    Electronic structure Kr 4d7 5s1
    Ionisation potential No. eV
    1 7.36
    2 16.8
    3 28.5
    Natural isotope distribution Mass No. %
    96 5.5
    98 1.9
    99 12.7
    100 12.6
    101 17.1
    102 31.6
    104 18.6
    Photo-electric work function ( eV ) 4.71
    Thermal neutron absorption cross-section ( Barns ) 3.0
    Valences shown 0, 1, 2, 3, 4, 5, 6, 7, 8
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 7.7
    Temperature coefficient @0-100C ( K-1 ) 0.0041
    Superconductivity critical temperature ( K ) 0.49
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     286
    Hardness - Vickers 350 750
    Poisson's ratio     0.25
    Tensile modulus ( GPa )     432
    Tensile strength ( MPa ) 495
    Yield strength ( MPa ) 372
  • Physical Properties
    Boiling point ( C ) 3900
    Density @20C ( g cm-3 ) 12.2
    Melting point ( C ) 2310
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 9.6
    Latent heat of evaporation ( J g-1 ) 5610
    Latent heat of fusion ( J g-1 ) 252
    Specific heat @25C ( J K-1 kg-1 ) 238
    Thermal conductivity @0-100C ( W m-1 K-1 ) 117

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Rutherfordium (Rf)

Rutherfordium

History

According to the Royal Society of Chemistry, in 1964, a team led by Georgy Flerov at the Russian Joint Institute for Nuclear Research (JINR) in Dubna, bombarded plutonium with neon and produced element 104, isotope 259. They confirmed their findings in 1966.

In 1969, a team led by Albert Ghiorso at the Californian Lawrence Berkeley Laboratory (LBL) made three successful attempts to produce element 104: by bombarding curium with oxygen to get isotope-260, californium with carbon to get isotope-257, and californium with carbon to get isotope-258.

A dispute over priority of discovery followed and eventually, in 1992, the International Unions of Pure and Applied Chemistry (IUPAC) concluded that both the Russian and American researchers had been justified in making their claims. IUPAC decided element 104 would be called rutherfordium.

  • Atomic Properties
    Atomic number 104
    Atomic weight ( amu ) (261)
    Electronic structure Rn 5f14 6d2 7s2
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Scandium (Sc)

Scandium

History

Scandium was discovered in 1879 by L.F. Nilson and takes its name from the Latin word "Scandia", meaning "Scandinavia".

Scandium is a soft, silvery white metal. It has been identified in several minerals, including cerite, orthite, thertveitite, wolframite and euxenite (a niobate, tantalate and titanate of several rare elements in which scandium was originally discovered). It is a metal which tarnishes in air (shows a pink colouration), burns easily and reacts with water to produce hydrogen gas.

Applications for scandium have not yet been fully investigated and its use is limited primarily to research.

Did you know?

  1. Scandium has great potential because it has almost as low a density as aluminium and a much higher melting point. An aluminium-scandium alloy has been used in Russian MIG fighter planes, high-end bicycle frames and baseball bats.
  2. Scandium iodide is added to mercury vapour lamps to produce a highly efficient light source resembling sunlight. These lamps help television cameras to reproduce colour well when filming indoors or at night-time.
  3. The radioactive isotope scandium-46 is used as a tracer in oil refining to monitor the movement of various fractions. It can also be used in underground pipes to detect leaks.
  • Atomic Properties
    Atomic number 21
    Atomic radius - Goldschmidt ( nm ) 0.160
    Atomic weight ( amu ) 44.9559
    Crystal structure Hexagonal close packed
    Electronic structure Ar 3d1 4s2
    Ionisation potential No. eV
    1 6.54
    2 12.8
    3 24.8
    4 73.5
    5 91.7
    6 111
    Natural isotope distribution Mass No. %
    45 100
    Photo-electric work function ( eV ) 3.5
    Thermal neutron absorption cross-section ( Barns ) 25
    Valences shown 3
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 66
    Temperature coefficient @0-100C ( K-1 ) 0.00282
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     44.2
    Hardness - Brinell 78 136
    Poisson's ratio     0.27
    Tensile modulus ( GPa )     79.3
  • Physical Properties
    Boiling point ( C ) 2831
    Density @20C ( g cm-3 ) 2.99
    Melting point ( C ) 1541
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 12
    Latent heat of evaporation ( J g-1 ) 7293
    Latent heat of fusion ( J g-1 ) 357
    Specific heat @25C ( J K-1 kg-1 ) 557
    Thermal conductivity @0-100C ( W m-1 K-1 ) 15.8

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Seaborgium (Sg)

Seaborgium

History

According to the Royal Society of Chemistry, in 1970, a team led by Albert Ghiorso at the Californian Lawrence Berkeley National Laboratory (LBNL) bombarded californium with oxygen and was successful in producing element 106, isotope 263. In 1974, a team led by Georgy Flerov and Yuri Oganessian at the Russian Joint Institute for Nuclear Research (JINR) bombarded lead with chromium and obtained isotopes 259 and 260.

Did you know?

  1. In September 1974, a team led by Ghiorso at LBNL produced isotope 263, with a half-life of 0.8 seconds, by bombarding californium with oxygen. Several atoms of seaborgium have since been made by this method which produces one seaborgium atom per hour.
  2. A radioactive metal that does not occur naturally. Only a few atoms have ever been made.
  3. The most stable known isotope, seaborgium-269, has a half-life of approximately 3.1 minutes.
  • Atomic Properties
    Atomic number 106
    Atomic weight ( amu ) (263)
    Electronic structure Rn 5f14 6d4 7s2
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Silver (Ag)

Silver

History

Silver was known to ancient civilisations. Silver is a soft, malleable metal with a characteristic sheen. It has the highest thermal and electrical conductivities of all metals. It is generally found uncombined, or in the sulphide or arsenide ores from which it can be recovered as a cyanide complex which is subsequently reduced to the metal, in aqueous solution, by the use of zinc. The pure metal is stable to water and oxygen but is attacked in air by sulphur bearing compounds to form the characteristic black layer of silver sulphide. It is soluble in sulphuric and nitric acids.

Did you know?

  1. Sterling silver contains 92.5% silver. The rest is copper or some other metal. It is used for jewellery and silver tableware, where appearance is important.
  2. Silver is used to make mirrors, as it is the best reflector of visible light known, although it does tarnish with time. It is also used in dental alloys, solder and brazing alloys, electrical contacts and batteries. Silver paints are used for making printed circuits.
  3. Silver bromide and iodide were important in the history of photography, because of their sensitivity to light. Even with the rise of digital photography, silver salts are still important in producing high-quality images and protecting against illegal copying. Light-sensitive glass (such as photochromic lenses) works on similar principles. It darkens in bright sunlight and becomes transparent in low sunlight.
  • Atomic Properties
    Atomic number 47
    Atomic radius - Goldschmidt ( nm ) 0.144
    Atomic weight ( amu ) 107.8682
    Crystal structure Face centred cubic
    Electronic structure Kr 4d1O 5s1
    Ionisation potential No. eV
    1 7.58
    2 21.5
    3 34.8
    Natural isotope distribution Mass No. %
    107 51.83
    109 48.17
    Photo-electric work function ( eV ) 4.7
    Thermal neutron absorption cross-section ( Barns ) 63.8
    Valences shown 1, 2
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 1.63
    Temperature coefficient @0-100C ( K-1 ) 0.0041
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) +0.74
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     103.6
    Hardness - Vickers 25 95
    Izod toughness ( J m-1 ) 5
    Poisson's ratio     0.367
    Tensile modulus ( GPa )     82.7
    Tensile strength ( MPa ) 172 330
  • Physical Properties
    Boiling point ( C ) 2212
    Density @20C ( g cm-3 ) 10.5
    Melting point ( C ) 961.9
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 19.1
    Latent heat of evaporation ( J g-1 ) 2390
    Latent heat of fusion ( J g-1 ) 103
    Specific heat @25C ( J K-1 kg-1 ) 237
    Thermal conductivity @0-100C ( W m-1 K-1 ) 429

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Tantalum (Ta)

Tantalum

History

Tantalum was discovered in 1802 by A.G. Ekeberg in Uppsala, Sweden.

Tantalum is a shiny, silvery coloured metal which is heavy, dense, malleable and ductile when pure. It is found in small quantities in minerals (generally in conjunction with niobium), and is isolated by conversion to the oxide and then the fluoro-complex, K2TaF7, from which the pure metal is obtained by electrolysis. Tantalum is extremely corrosion resistant due to the formation of an oxide film, and is also resistant to acid attack (with the exception of HF). It will react with fused alkalis and a variety of non-metals at elevated temperatures.

Did you know?

  1. Tantalum can be used as a replacement for platinum for laboratory apparatus which has to have good corrosion resistance, and the metal is also used within the chemical industry for similar reasons. The fluids in the human body do not react with the metal and, hence, it is used for surgical implants without rejection.
  2. The pure metal is used in the electronics industry in the manufacture of various types of electronic equipment (e.g. rectifiers, capacitors, lamp filaments, etc.). Other applications include the use of tantalum carbide in cemented carbides which are used as cutting tools.
  3. Tantalum is also used in vacuum systems as it has a high absorption rate for residual gases. It is also used as an alloying element with, for example, nickel and molybdenum, to produce alloys which have good corrosion resistance, strength and ductility.
  • Atomic Properties
    Atomic number 73
    Atomic radius - Goldschmidt ( nm ) 0.147
    Atomic weight ( amu ) 180.9479
    Crystal structure Body centred cubic
    Electronic structure Xe 4f14 5d3 6s2
    Ionisation potential No. eV
    1 7.88
    2 16.2
    Natural isotope distribution Mass No. %
    180 0.012
    181 99.988
    Photo-electric work function ( eV ) 4.1
    Thermal neutron absorption cross-section ( Barns ) 22
    Valences shown 2, 3, 4, 5
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 13.5
    Temperature coefficient @0-100C ( K-1 ) 0.0035
    Superconductivity critical temperature ( K ) 4.47
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) +0.33
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     196.3
    Hardness - Vickers 90 200
    Poisson's ratio     0.342
    Tensile modulus ( GPa )     185.7
    Tensile strength ( MPa ) 172-207 760
    Yield strength ( MPa ) 310-380 705
  • Physical Properties
    Boiling point ( C ) 5425
    Density @20C ( g cm-3 ) 16.6
    Melting point ( C ) 2996
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 6.5
    Latent heat of evaporation ( J g-1 ) 4165
    Latent heat of fusion ( J g-1 ) 174
    Specific heat @25C ( J K-1 kg-1 ) 140
    Thermal conductivity @0-100C ( W m-1 K-1 ) 57.5

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Technetium (Tc)

Technetium

History

According to the Royal Society of Chemistry, Technetium long tantalised chemists because it could not be found. We now know that all its isotopes are radioactive and any mineral deposits of the element had long disappeared from the Earth’s crust. (The longest lived isotope has a half life of 4 million years.)

Even so, some technetium atoms are produced as uranium undergoes nuclear fission and there is about 1 milligram of technetium in a tonne of uranium. Claims in the 1920s to have found this element, or at least to have observed its spectrum, cannot be entirely discounted.

Technetium was discovered by Emilio Segrè in 1937 in Italy. He investigated molybdenum from California which had been exposed to high energy radiation and he found technetium to be present and separated it. Today, this element is extracted from spent nuclear fuel rods in tonne quantities.

Did you know?

  1. The gamma-ray emitting technetium-99m (metastable) is widely used for medical diagnostic studies. Several chemical forms are used to image different parts of the body.
  2. Technetium is a remarkable corrosion inhibitor for steel, and adding very small amounts can provide excellent protection. This use is limited to closed systems as technetium is radioactive.
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Titanium (Ti)

Titanium

History

Titanium was discovered by Rev. William Gregor in 1791 in Creed, Cornwall, England and, independently, by M.H. Klaproth in 1795 in Berlin, Germany.

Titanium is a hard, lustrous, silvery metal which is obtained by magnesium or calcium reduction of the tetrachloride. It is a relatively abundant element, there being 5600 ppm in the earth's crust. It forms a protective oxide coating and, hence, resists corrosion, although powdered metal burns in air. Titanium tends to be inert at low temperatures but will combine with a variety of reagents at elevated temperatures.

Titanium and its alloys are characterised by their lightness, strength and corrosion resistance and are used widely in aerospace applications. In addition, these properties also make the material suitable for medical applications (e.g. replacement hip joints). Titanium dioxide, TiO2 is used as a white pigment in paints and plastics as it provides great opacity. The same material is also used in the manufacture of heat resisting and durable glass, the TiO2 replacing certain proportions of the soda. Titanium carbide is used to manufacture cemented carbides.

Did you know?

  1. Titanium is the ninth most abundant element on Earth. It is almost always present in igneous rocks and the sediments derived from them. It occurs in the minerals ilmenite, rutile and sphene and is present in titanates and many iron ores.
  2. Power plant condensers use titanium pipes because of their resistance to corrosion. Because titanium has excellent resistance to corrosion in seawater, it is used in desalination plants and to protect the hulls of ships, submarines and other structures exposed to seawater.
  3. Titanium metal connects well with bone, so it has found surgical applications such as in joint replacements (especially hip joints) and tooth implants.
  • Atomic Properties
    Atomic number 22
    Atomic radius - Goldschmidt ( nm ) 0.147
    Atomic weight ( amu ) 47.88
    Crystal structure Hexagonal close packed
    Electronic structure Ar 3d2 4s2
    Ionisation potential No. eV
    1 6.82
    2 13.6
    3 27.5
    4 43.3
    5 99.2
    6 119
    Natural isotope distribution Mass No. %
    46 8.0
    47 7.5
    48 73.7
    49 5.5
    50 5.3
    Photo-electric work function ( eV ) 4.1
    Thermal neutron absorption cross-section ( Barns ) 6.1
    Valences shown 2, 3, 4
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 54
    Temperature coefficient @0-100C ( K-1 ) 0.0038
    Superconductivity critical temperature ( K ) 0.40
  • Mechanical Properties
    Material condition Annealed Polycrystalline
    Bulk modulus ( GPa )   108.4
    Hardness - Vickers 60
    Izod toughness ( J m-1 ) 61
    Poisson's ratio   0.361
    Tensile modulus ( GPa )   120.2
    Tensile strength ( MPa ) 230-460
    Yield strength ( MPa ) 140-250
  • Physical Properties
    Boiling point ( C ) 3287
    Density @20C ( g cm-3 ) 4.5
    Melting point ( C ) 1660
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 8.9
    Latent heat of evaporation ( J g-1 ) 8893
    Latent heat of fusion ( J g-1 ) 365
    Specific heat @25C ( J K-1 kg-1 ) 523
    Thermal conductivity @0-100C ( W m-1 K-1 ) 21.9

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Tungsten (W)

Tungsten

History

Tungsten was isolated in 1783 by J.J. and F. Elhuyar in Vergara, Spain.

Tungsten metal is lustrous and silvery white in colour, and does not occur naturally (it has an abundance of 1 ppm in the earth's crust). It is found in the ore Wolframite, a tungstate of iron and manganese, (FeMn)WO4, which is converted to the trioxide and then reduced to the metal by reduction in hydrogen (carbon cannot be used as the very stable carbide would result). Tungsten metal is relatively inert, resisting attack by oxygen, acids and alkalis, although it will react with fused, oxidising alkali media. It has the highest melting point of all metals and, when pure, it can be worked with relative ease; however, the presence of impurities renders tungsten extremely brittle and, therefore, difficult to fabricate.

The high melting point of tungsten makes it suitable for use as electric filaments (e.g. in electric light bulbs). It is also the basis of a range of alloys containing tungsten, copper and nickel which are used for radiation shielding as they provide a 50% increase in density compared to lead. Tungsten and its alloys also find uses in military applications (e.g. armour and shells), as well as counter-balance materials. Tungsten carbide powder (with possible additions of titanium and tantalum carbides) along with nickel or cobalt powders, are compressed and sintered to produce cemented carbides. These products are used in place of high speed steel to form the tip of cutting and drilling tools, or for parts which will be subjected to heavy usage.

Did you know?

  1. Tungsten was used extensively for the filaments of old-style incandescent light bulbs, but these have been phased out in many countries. This is because they are not very energy efficient; they produce much more heat than light.
  2. Tungsten has the highest melting point of all metals and is alloyed with other metals to strengthen them. Tungsten and its alloys are used in many high-temperature applications, such as arc-welding electrodes and heating elements in high-temperature furnaces.
  3. Tungsten carbide is immensely hard and is very important to the metal-working, mining and petroleum industries. It is made by mixing tungsten powder and carbon powder and heating to 2200°C. It makes excellent cutting and drilling tools, including a new ‘painless’ dental drill which spins at ultra-high speeds.
  • Atomic Properties
    Atomic number 74
    Atomic radius - Goldschmidt ( nm ) 0.141
    Atomic weight ( amu ) 183.85
    Crystal structure Body centred cubic
    Electronic structure Xe 4f14 5d4 6s2
    Ionisation potential No. eV
    1 7.98
    2 17.7
    Natural isotope distribution Mass No. %
    180 0.1
    182 26.3
    183 14.3
    184 30.7
    186 28.6
    Photo-electric work function ( eV ) 4.55
    Thermal neutron absorption cross-section ( Barns ) 18.5
    Valences shown 2, 3, 4, 5, 6
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 5.4
    Temperature coefficient @0-100C ( K-1 ) 0.0048
    Superconductivity critical temperature ( K ) 0.0154
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) +1.12
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     311
    Hardness - Vickers 360 500
    Poisson's ratio     0.28
    Tensile modulus ( GPa )     411
    Tensile strength ( MPa ) 550-620 1920
    Yield strength ( MPa ) 550
  • Physical Properties
    Boiling point ( C ) 5660
    Density @20C ( g cm-3 ) 19.3
    Melting point ( C ) 3410
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 4.5
    Latent heat of evaporation ( J g-1 ) 4009
    Latent heat of fusion ( J g-1 ) 192
    Specific heat @25C ( J K-1 kg-1 ) 133
    Thermal conductivity @0-100C ( W m-1 K-1 ) 173

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Vanadium (V)

Vanadium

History

Vanadium was discovered in Mexico City in 1801 by A.M. del Rio, and was rediscovered in 1831 by N.G. Selfström in Falun, Sweden.

Vanadium is a soft, shiny, silvery metal which can be found in many different minerals, including some crude oils. It has an abundance of 160 ppm in the earth's crust and can be isolated after conversion to the pentoxide, V2O5, followed by direct reduction with aluminium. High purity metal can be obtained by the van Arkel process in which the iodide is decomposed on a hot filament under vacuum. Pure vanadium resists corrosion due to the formation of a protective oxide film on its surface; it is attacked by concentrated acids but not by fused alkalis.

The principal use for vanadium is as an alloying constituent, particularly in steels where it is introduced as ferrovanadium, an alloy of iron and vanadium. The addition of vanadium to steels removes occluded oxygen and nitrogen, thus improving the materials' strength. A typical vanadium content would be 0.5% max.

Did you know?

  1. Vanadium is essential to some species, including humans, although we need very little. We take in just 0.01 milligrams each day, and this is more than sufficient for our needs. In some compounds vanadium can become toxic.
  2. Pure vanadium was produced by Henry Roscoe at Manchester, in 1869, and he showed that previous samples of the metal were really vanadium nitride (VN).
  3. Vanadium-steel alloys are very tough and are used for armour plate, axles, tools, piston rods and crankshafts. Less than 1% of vanadium, and as little chromium, makes steel shock resistant and vibration resistant. Vanadium alloys are used in nuclear reactors because of vanadium’s low neutron-absorbing properties.
  • Atomic Properties
    Atomic number 23
    Atomic radius - Goldschmidt ( nm ) 0.136
    Atomic weight ( amu ) 50.9415
    Crystal structure Body centred cubic
    Electronic structure Ar 3d3 4s2
    Ionisation potential No. eV
    1 6.74
    2 14.6
    3 29.3
    4 46.7
    5 65.2
    6 128
    Natural isotope distribution Mass No. %
    50 0.25
    51 99.75
    Photo-electric work function ( eV ) 4.3
    Thermal neutron absorption cross-section ( Barns ) 5.06
    Valences shown 2, 3, 4, 5
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 19.6
    Temperature coefficient @0-100C ( K-1 ) 0.0039
    Superconductivity critical temperature ( K ) 5.40
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) 0.63
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     158
    Hardness - Vickers 80 150
    Izod toughness ( J m-1 ) 10-136
    Poisson's ratio     0.365
    Tensile modulus ( GPa )     127.6
    Tensile strength ( MPa ) 260-585 530-730
    Yield strength ( MPa ) 170-450 515-690
  • Physical Properties
    Boiling point ( C ) 3380
    Density @20C ( g cm-3 ) 6.1
    Melting point ( C ) 1890
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 8.3
    Latent heat of evaporation ( J g-1 ) 8975
    Latent heat of fusion ( J g-1 ) 345
    Specific heat @25C ( J K-1 kg-1 ) 486
    Thermal conductivity @0-100C ( W m-1 K-1 ) 30.7

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Yttrium (Y)

Yttrium

History

Yttrium was discovered by J. Gadolin in Åbo, Finland, in 1794.

Yttrium is a lanthanide group metal which is found in most rare earth minerals, particularly yttrotantalite which, whilst containing yttrium and tantalum, also contains niobium, cerium, uranium, iron and calcium in varying amounts. The mineral is found in Ytterby, Sweden, the town which gave its name to several elements. Yttrium has an abundance of 30 ppm in the earth's crust. The metal is stable in air due to the formation of an oxide film, but it will burn easily and will react with water to produce hydrogen.

Did you know?

  1. Yttrium-aluminium garnet (YAG) is used in lasers that can cut through metals. It is also used in white LED lights.
  2. Yttrium oxide is added to the glass used to make camera lenses to make them heat and shock resistant. It is also used to make superconductors. Yttrium oxysulfide used to be widely used to produce red phosphors for old-style colour television tubes.
  3. The radioactive isotope yttrium-90 has medical uses. It can be used to treat some cancers, such as liver cancer.
  • Atomic Properties
    Atomic number 39
    Atomic radius - Goldschmidt ( nm ) 0.181
    Atomic weight ( amu ) 88.9059
    Crystal structure Hexagonal close packed
    Electronic structure Kr 4d1 5s2
    Ionisation potential No. eV
    1 6.38
    2 12.2
    3 20.5
    4 61.8
    5 77
    6 93
    Natural isotope distribution Mass No. %
    89 100
    Photo-electric work function ( eV ) 3.1
    Thermal neutron absorption cross-section ( Barns ) 1.3
    Valences shown 3
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 66
    Temperature coefficient @0-100C ( K-1 ) 0.00282
  • Mechanical Properties
    Material condition Soft Hard Polycrystalline
    Bulk modulus ( GPa )     37.3
    Hardness - Brinell 30-60 100-140
    Izod toughness ( J m-1 ) 24
    Poisson's ratio     0.265
    Tensile modulus ( GPa )     66.3
    Tensile strength ( MPa ) 130 455
    Yield strength ( MPa ) 57 375
  • Physical Properties
    Boiling point ( C ) 3338
    Density @20C ( g cm-3 ) 4.478
    Melting point ( C ) 1522
  • Thermal Properties
    Coefficient of thermal expansion @0-400C ( x10-6 K-1 ) 10.8
    Latent heat of evaporation ( J g-1 ) 4135
    Latent heat of fusion ( J g-1 ) 193
    Specific heat @25C ( J K-1 kg-1 ) 285
    Thermal conductivity @0-100C ( W m-1 K-1 ) 17.2

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Zinc (Zn)

Zinc

History

Zinc was known to the Greeks and Romans as a constituent of the copper alloy, brass, but metallic zinc was not discovered until the 16th. century by Paracelcus.

Zinc is a brittle metal which has a blue cast. It is readily accessible as it occurs in concentrated ores from which it is easily extracted (it has an abundance of 75 ppm in the earth's crust). Extraction is achieved by heating the oxide with carbon and distilling out the metal. Zinc tarnishes in air and reacts with acids and alkalis.

Zinc is used widely throughout industry; for example, it is used as a galvanic coating on steel to prevent corrosion, and is used as a constituent of various alloy systems (e.g. with copper in brass), as well as in zinc-base alloys which can be used for diecasting (the other alloy constituents are aluminium, copper and magnesium). Pure zinc is used as an electrode in a Daniell cell and also in dry batteries. Zinc oxide is used as a stabiliser for certain grades of rubbers and plastics, as well as a non-toxic, white pigment used in paint manufacture. Zinc oxide also has astringent and soothing qualities and is used as a constituent of creams and ointments.

Did you know?

  1. Zinc is essential for all living things, forming the active site in over 20 metallo-enzymes. The average human body contains about 2.5 grams and takes in about 15 milligrams per day. Some foods have above average levels of zinc, including herring, beef, lamb, sunflower seeds and cheese.
  2. Zinc can be carcinogenic in excess. If freshly formed zinc(II) oxide is inhaled, a disorder called the ‘oxide shakes’ or ‘zinc chills’ can occur.
  3. Zinc oxide is widely used in the manufacture of very many products such as paints, rubber, cosmetics, pharmaceuticals, plastics, inks, soaps, batteries, textiles and electrical equipment. Zinc sulfide is used in making luminous paints, fluorescent lights and x-ray screens.
  • Atomic Properties
    Atomic number 30
    Atomic radius - Goldschmidt ( nm ) 0.137
    Atomic weight ( amu ) 65.38
    Crystal structure Hexagonal close packed
    Electronic structure Ar 3d1O 4s2
    Ionisation potential No. eV
    1 9.39
    2 17.96
    3 39.7
    4 59.4
    5 82.6
    6 108
    Natural isotope distribution Mass No. %
    64 48.6
    66 27.9
    67 4.1
    68 18.8
    70 0.6
    Photo-electric work function ( eV ) 4.3
    Thermal neutron absorption cross-section ( Barns ) 1.10
    Valences shown 2
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 5.96
    Temperature coefficient @0-100C ( K-1 ) 0.0042
    Superconductivity critical temperature ( K ) 0.85
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) +0.76
  • Mechanical Properties
    Material condition Polycrystalline
    Bulk modulus ( GPa ) 69.4
    Hardness - Mohs 2.5
    Poisson's ratio 0.249
    Tensile modulus ( GPa ) 104.5
  • Physical Properties
    Boiling point ( C ) 907
    Density @20C ( g cm-3 ) 7.14
    Melting point ( C ) 419.5
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 31.0
    Latent heat of evaporation ( J g-1 ) 1748
    Latent heat of fusion ( J g-1 ) 111
    Specific heat @25C ( J K-1 kg-1 ) 388
    Thermal conductivity @0-100C ( W m-1 K-1 ) 116

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Zirconium (Zr)

Zirconium

History

Zirconium was discovered in Berlin, Germany, in 1789 by M.H. Klaproth, but was not isolated until 1824 by J.J. Berzelius in Stockholm, Sweden.

Zirconium is a hard, lustrous, silvery coloured metal which is extracted from its ores (the oxide or zircon, ZrSiO4) by conversion to the tetrahalide followed by reduction with magnesium. The metal is extremely corrosion resistant due to the formation of a stable oxide film and is unaffected by acids (with the exception of HF) and alkalis.

As a result of its corrosion resistance, zirconium is widely used in the chemical industry where corrosive agents are used. Also, due to its excellent high temperature properties, coupled with its low neutron absorption, it is used in the construction of nuclear reactors. The pure metal is also used as a lining in jet engines. Zirconium is used as an alloying element, the resultant alloys having improved mechanical properties.

The chemical properties of zirconium are very similar to those of hafnium. As a result, the normal chemical processes used for the extraction of zirconium will not remove hafnium, which can be present in commercial grades of zirconium at levels as high as 4.5%. A high purity grade of zirconium containing less than 0.01% hafnium is used for nuclear applications.

Did you know?

  1. Zirconium(IV) oxide is used in ultra-strong ceramics. It is used to make crucibles that will withstand heat-shock, furnace linings, foundry bricks, abrasives and by the glass and ceramics industries. It is so strong that even scissors and knives can be made from it. It is also used in cosmetics, antiperspirants, food packaging and to make microwave filters.
  2. Zircon is a natural semi-precious gemstone found in a variety of colours. The most desirable have a golden hue. The element was first discovered in this form, resulting in its name. Cubic zirconia (zirconium oxide) is a synthetic gemstone. The colourless stones, when cut, resemble diamonds.
  3. Zircon mixed with vanadium or praseodymium makes blue and yellow pigments for glazing pottery.
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International Comparisons of Tertiary Chemistry Education

A recent project has been completed by the Committee on Chemistry Education highlighting the disparities and commonalities of chemistry education. Taken from the IUPAC website, the project objective was as follows:

“Learning outcome driven chemistry education is increasingly practiced, providing new opportunities for international comparisons. We will develop a method for benchmarking (i.e. learning by sharing and comparing best practice) these outcomes, to enhance learner-centered chemistry education both in the developed and developing world. The project builds on and extends task group members experiences from national and international projects.”


Read More Here >>
  • Atomic Properties
    Atomic number 40
    Atomic radius - Goldschmidt ( nm ) 0.160
    Atomic weight ( amu ) 91.22
    Crystal structure Hexagonal close packed
    Electronic structure Kr 4d2 5s2
    Ionisation potential No. eV
    1 6.84
    2 13.13
    3 22.99
    4 34.34
    5 81.5
    6 99
    Natural isotope distribution Mass No. %
    90 51.4
    91 11.2
    92 17.1
    94 17.5
    96 2.8
    Photo-electric work function ( eV ) 3.8
    Thermal neutron absorption cross-section ( Barns ) 0.182
    Valences shown 2, 3, 4
  • Electrical Properties
    Electrical resistivity @20C ( µOhmcm ) 44
    Temperature coefficient @0-100C ( K-1 ) 0.0044
    Superconductivity critical temperature ( K ) 0.61
    Thermal emf against Pt (cold 0C - hot 100C) ( mV ) +1.17
  • Mechanical Properties
    Material condition Soft Polycrystalline
    Bulk modulus ( GPa )   89.8
    Hardness - Vickers 85-100
    Poisson's ratio   0.38
    Tensile modulus ( GPa )   98
    Tensile strength ( MPa ) 350-390
    Yield strength ( MPa ) 250-310
  • Physical Properties
    Boiling point ( C ) 4377
    Density @20C ( g cm-3 ) 6.49
    Melting point ( C ) 1852
  • Thermal Properties
    Coefficient of thermal expansion @0-100C ( x10-6 K-1 ) 5.9
    Latent heat of evaporation ( J g-1 ) 6360
    Latent heat of fusion ( J g-1 ) 211
    Specific heat @25C ( J K-1 kg-1 ) 281
    Thermal conductivity @0-100C ( W m-1 K-1 ) 22.7

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