Tellurium

Tellurium, ₅₂Te

Tellurium
Pronunciation	/tɛˈljʊəriəm/ ​(te-LURE-ee-əm)
Appearance	silvery lustrous gray (crystalline), brown-black powder (amorphous)
Standard atomic weight Ar°(Te)
	127.60±0.03[1] 127.60±0.03 (abridged)[2]
Tellurium in the periodic table
Hydrogen Helium Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson Se ↑ Te ↓ Po antimony ← tellurium → iodine
Atomic number (Z)	52
Group	group 16 (chalcogens)
Period	period 5
Block	p-block
Electron configuration	[Kr] 4d10 5s2 5p4
Electrons per shell	2, 8, 18, 18, 6
Physical properties
Phase at STP	solid
Melting point	722.66 K ​(449.51 °C, ​841.12 °F)
Boiling point	1261 K ​(988 °C, ​1810 °F)
Density (at 20° C)	6.237 g/cm3[3]
when liquid (at m.p.)	5.70 g/cm3
Heat of fusion	17.49 kJ/mol
Heat of vaporization	114.1 kJ/mol
Molar heat capacity	25.73 J/(mol·K)
Vapor pressure P (Pa) 1 10 100 1 k 10 k 100 k at T (K)   (775) (888) 1042 1266
Atomic properties
Oxidation states	common: −2, +2, +4, +6 −1,? 0,? +1,? +3,? +5[4]
Electronegativity	Pauling scale: 2.1
Ionization energies	1st: 869.3 kJ/mol 2nd: 1790 kJ/mol 3rd: 2698 kJ/mol
Atomic radius	empirical: 140 pm
Covalent radius	138±4 pm
Van der Waals radius	206 pm
Spectral lines of tellurium
Other properties
Natural occurrence	primordial
Crystal structure	​hexagonal[5] (hP3)
Lattice constants	a = 445.59 pm c = 592.75 pm (at 20 °C)[3]
Thermal expansion	19.0×10−6/K (at 20 °C)[a]
Thermal conductivity	1.97–3.38 W/(m⋅K)
Magnetic ordering	diamagnetic[6]
Molar magnetic susceptibility	−39.5×10−6 cm3/mol (298 K)[7]
Young's modulus	43 GPa
Shear modulus	16 GPa
Bulk modulus	65 GPa
Speed of sound thin rod	2610 m/s (at 20 °C)
Mohs hardness	2.25
Brinell hardness	180–270 MPa
CAS Number	13494-80-9
History
Naming	after Roman Tellus, deity of the Earth
Discovery	Franz-Joseph Müller von Reichenstein (1782)
First isolation	Martin Heinrich Klaproth
Isotopes of tellurium v e
Main isotopes[8] Decay abun­dance half-life (t1/2) mode pro­duct 120Te 0.09% stable 121Te synth 16.78 d ε 121Sb 122Te 2.55% stable 123Te 0.89% stable[9] 124Te 4.74% stable 125Te 7.07% stable 126Te 18.8% stable 127Te synth 9.35 h β− 127I 128Te 31.7% 2.2×1024 y β−β− 128Xe 129Te synth 69.6 min β− 129I 130Te 34.1% 7.91×1020 y β−β− 130Xe
Category: Tellurium view talk edit | references

Tellurium is a chemical element; it has symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally found in its native form as elemental crystals. Tellurium is far more common in the Universe as a whole than on Earth. Its extreme rarity in the Earth's crust, comparable to that of platinum, is due partly to its formation of a volatile hydride that caused tellurium to be lost to space as a gas during the hot nebular formation of Earth.^[10]

Tellurium-bearing compounds were first discovered in 1782 in a gold mine in Kleinschlatten, Transylvania (now Zlatna, Romania) by Austrian mineralogist Franz-Joseph Müller von Reichenstein, although it was Martin Heinrich Klaproth who named the new element in 1798 after the Latin tellus 'earth'. Gold telluride minerals are the most notable natural gold compounds. However, they are not a commercially significant source of tellurium itself, which is normally extracted as a by-product of copper and lead production.

Commercially, the primary use of tellurium is CdTe solar panels and thermoelectric devices. A more traditional application in copper (tellurium copper) and steel alloys, where tellurium improves machinability, also consumes a considerable portion of tellurium production. Tellurium is considered a technology-critical element.^[11]

Tellurium has no biological function, although fungi can use it in place of sulfur and selenium in amino acids such as tellurocysteine and telluromethionine.^[12] In humans, tellurium is partly metabolized into dimethyl telluride, (CH₃)₂Te, a gas with a garlic-like odor exhaled in the breath of victims of tellurium exposure or poisoning.

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