|
52
Te
127.6
|
| Classification: | Tellurium is a chalcogen and a metalloid |
| Color: | silvery |
| Atomic weight: | 127.60 |
| State: | solid |
| Melting point: | 450 oC, 723 K |
| Boiling point: | 990 oC, 1263 K |
| Shells: | 2,8,18,18,6 |
| Electron configuration: | [Kr] 4d10 5s2 5p4 |
| Density @ 20oC: | 6.24 g/cm3 |
| Atomic volume: | 20.5 cm3/mol |
| Structure: | parallel chains |
| Hardness: | 2.3 mohs |
Discovery of Tellurium
Tellurium was discovered by Baron Franz Muller von Reichenstein in 1783.
Martin H. Klaproth isolated the element and named it in 1798.
The element name comes from the Latin word 'tellus' meaning Earth.
Appearance & Characteristics
Hubble Telescope Wide Field Camera 3.
The crystalline photosensitive surface of the camera's near-infrared detector is composed of mercury,
cadmium and tellurium (HgCdTe). (NASA)
Harmful effects:
Tellerium is very toxic and teratogenic (can cause harm to developing embryos). Exposure to as little as 0.01 mg/m2 or less in air leads to "tellurium breath", which has a garlic-like odor.
Characteristics:
Tellurium is a rare, silvery-white, brittle, lustrous metalloid. It burns in air with a greenish-blue flame and forms tellurium dioxide (TeO2). Tellurium is a semiconductor material and is slightly photosensitive. It forms many compounds corresponding to those of sulfur and selenium, the elements above it in the periodic table. Tellurium has radioactive isotopes and is the lightest element to exhibit alpha decay.
Tellurium is alloyed with copper and stainless steel to make these metals more workable. It is added to lead to decreases the corrosive action of sulfuric acid and to improve its strength and hardness. Tellurium is used as a coloring agent in ceramics. Tellurium is also used in the electronic industry, for example with cadmium and mercury to form photosensitive semiconductors. It is used in vulcanizing rubber and in catalysts for petroleum cracking and in blasting caps for explosives.
Tellerium is very toxic and teratogenic (can cause harm to developing embryos). Exposure to as little as 0.01 mg/m2 or less in air leads to "tellurium breath", which has a garlic-like odor.
Characteristics:
Tellurium is a rare, silvery-white, brittle, lustrous metalloid. It burns in air with a greenish-blue flame and forms tellurium dioxide (TeO2). Tellurium is a semiconductor material and is slightly photosensitive. It forms many compounds corresponding to those of sulfur and selenium, the elements above it in the periodic table. Tellurium has radioactive isotopes and is the lightest element to exhibit alpha decay.
Uses of Tellurium
Tellurium is alloyed with copper and stainless steel to make these metals more workable. It is added to lead to decreases the corrosive action of sulfuric acid and to improve its strength and hardness. Tellurium is used as a coloring agent in ceramics. Tellurium is also used in the electronic industry, for example with cadmium and mercury to form photosensitive semiconductors. It is used in vulcanizing rubber and in catalysts for petroleum cracking and in blasting caps for explosives.
Abundance & Isotopes
Abundance earth's crust: 1 part per billion by weight, 0.2 parts per billion by moles
Abundance solar system:
Cost, pure: $24 per 100g
Cost, bulk: $0.44 per 100g
Source: Tellurium is sometimes found free in nature. More commonly, it is found combined with metals, such as in the minerals calaverite (gold telluride, AuTe2) and sylvanite (silver-gold telluride). Commercially, tellurium is obtained as a byproduct of electrolytic copper refining.
Isotopes: Tellurium has 33 isotopes whose half-lives are known, with mass numbers 106 to 138. Of these, five are stable: 120Te, 122Te, 124Te, 125Te and 126Te.
Abundance solar system:
Cost, pure: $24 per 100g
Cost, bulk: $0.44 per 100g
Source: Tellurium is sometimes found free in nature. More commonly, it is found combined with metals, such as in the minerals calaverite (gold telluride, AuTe2) and sylvanite (silver-gold telluride). Commercially, tellurium is obtained as a byproduct of electrolytic copper refining.
Isotopes: Tellurium has 33 isotopes whose half-lives are known, with mass numbers 106 to 138. Of these, five are stable: 120Te, 122Te, 124Te, 125Te and 126Te.
Energies
Specific heat capacity: 0.20 J/gK
Heat of fusion: 17.490 kJ mol-1
1st ionization energy: 869.2 kJ mol-1
3rd ionization energy: 2697.7 kJ mol-1
Heat of fusion: 17.490 kJ mol-1
1st ionization energy: 869.2 kJ mol-1
3rd ionization energy: 2697.7 kJ mol-1
Heat of atomization: 197 kJ mol-1
Heat of vaporization: 52.550 kJ mol-1
2nd ionization energy: 1794.6 kJ mol-1
Electron affinity: 190.16 kJ mol-1
Heat of vaporization: 52.550 kJ mol-1
2nd ionization energy: 1794.6 kJ mol-1
Electron affinity: 190.16 kJ mol-1
Oxidation & Electrons
Shells: 2,8,18,18,6
Minimum oxidation number: -2
Min. common oxidation no.: 0
Electronegativity (Pauling Scale): 2.1
Minimum oxidation number: -2
Min. common oxidation no.: 0
Electronegativity (Pauling Scale): 2.1
Electron configuration: [Kr] 4d10 5s2 5p4
Maximum oxidation number: 6
Max. common oxidation no.: 6
Polarizability volume: 5.5 Å3
Maximum oxidation number: 6
Max. common oxidation no.: 6
Polarizability volume: 5.5 Å3
Reactions & Compounds
Reaction with air: mild, w/ht ⇒ TeO2
Reaction with 15 M HNO3: mild , ⇒ Te(IV)
Oxide(s): TeO2, TeO3
Hydride(s): TeH2 (hydrogen telluride)
Reaction with 15 M HNO3: mild , ⇒ Te(IV)
Oxide(s): TeO2, TeO3
Hydride(s): TeH2 (hydrogen telluride)
Reaction with 6 M HCl: none
Reaction with 6 M NaOH: none
Chloride(s): Te2Cl, Te3Cl2, Te4Cl16
Reaction with 6 M NaOH: none
Chloride(s): Te2Cl, Te3Cl2, Te4Cl16
Radius
Atomic radius: 142 pm
Ionic radius (2+ ion): pm
Ionic radius (2- ion): 207 pm
Ionic radius (2+ ion): pm
Ionic radius (2- ion): 207 pm
Ionic radius (1+ ion): pm
Ionic radius (3+ ion): 90 pm
Ionic radius (1- ion): pm
Ionic radius (3+ ion): 90 pm
Ionic radius (1- ion): pm
Conductivity
Thermal conductivity: 3 W m-1 K-1
Electrical conductivity: 0.0002 x 106 S m-1
References
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