Tellurium

Tellurium - Te

CAS: 13494-80-9
Description: Silvery-white, metal-like
Classification: Metalloid
Date of Discovery: 1728
Discoverer: Franz Muller von Reichenstein
Name Origin: Latin tellus, "Earth"

Atomic Number: 52
Number of Neutrons: 76
Atomic Mass: 127.60(3) amu
Melting Point: 449.51 ± 0.3 °C
Boiling Point: 988 °C
Density (293 K): 6.24 g/cm³
Atomic volume: 20.5 cm³/mol
Electrical resistivity: 2.0 e^-6 10⁶/cm

Thermal conductivity: 0.0235 W/cmK
Enthalpy of atomization: 190.37 kJ/mol
Enthalpy of vaporization: 52.550 kJ/mol
Enthalpy of fusion: 17.490 kJ/mol
Specific heat capacity: 0.20 J/gK

Energy levels: 2-8-18-18-6
Electron configuration: [Kr]4d¹⁰5s²5p⁴
Crystal Structure: Hexagonal
Atomic radius: 1.42 Å
Covalent radius: 1.36 Å
Oxidation States: -2, +4, +6
Electronegativity, Pauling: 2.1
Electron affinity: 1.9708 eV
First ionization energy: 9.009 eV
2nd ionization energy: 18.60 eV
3rd ionization energy: 27.96 eV
Polarizability: 5.5 10^-24cm³

Isotope	Natural Abundance	Atomic Mass	Half-life	Decay Mode	Spin
¹⁰⁶Te	105.9377	0.06 ms
¹⁰⁷Te	106.9350	3.1 ms	; ⁺; EC
¹⁰⁸Te	107.9295	2.1 s	; ⁺	0+
¹⁰⁹Te	108.9275	4.6 s	⁺, EC;
¹¹⁰Te	109.9224	19 s	⁺, EC	0+
¹¹¹Te	110.9211	19.3 s	⁺, EC	(7/2+)
¹¹²Te	111.9171	2.0 m	⁺; EC	0+
¹¹³Te	112.9154	1.7 s	⁺; EC	(7/2+)
¹¹⁴Te	113.9125	15 m	⁺; EC	0+
^115mTe	6.7 m	⁺; EC	(1/2+)
¹¹⁵Te	114.9116	5.8 m	⁺; EC	7/2+
¹¹⁶Te	115.9084	2.49 h	EC	0+
¹¹⁷Te	116.90864	1.03 h	EC; ⁺	1/2+
¹¹⁸Te	117.90583	6.00 d	EC	0+
^119mTe	4.69 d	EC	11/2-
¹¹⁹Te	118.90641	16.0 h	⁺; EC	1/2+
¹²⁰Te	0.096(2)	119.90403	Stable	0+
^121mTe	154 d	IT; EC	11/2-
¹²¹Te	120.90494	16.8 d	EC	1/2+
¹²²Te	2.603(4)	121.903056	Stable	0+
^123mTe	119.7 d	IT	11/2-
¹²³Te	0.908(2)	122.904271	1.3 x 10¹³ y	EC	1/2+
¹²⁴Te	4.816(6)	123.902819	Stable	0+
^125mTe	58 d	IT	11/2-
¹²⁵Te	7.139(6)	124.904424	Stable	1/2+
¹²⁶Te	18.952(1)	125.903305	Stable	0+
^127mTe	109 d	IT; ^-	11/2-
¹²⁷Te	126.905217	9.4 h	^-	3/2+
¹²⁸Te	31.687(11)	127.904462	Stable	0+
^129mTe	33.6 d	IT; ^-	11/2-
¹²⁹Te	128.906596	1.16 h	^-	3/2+
¹³⁰Te	33.799(10)	129.906233	2.5 x 10²¹ y	^-	0+
^131mTe	1.35 d	^-; IT	11/2-
¹³¹Te	130.908522	25.0 m	^-	3/2+
¹³²Te	131.90852	3.26 d	^-	0+
^133mTe	55.4 m	^-; IT	11/2-
¹³³Te	132.9109	12.4 m	^-	3/2+
¹³⁴Te	133.9116	42 m	^-	0+
¹³⁵Te	134.9165	19.0 s	^-
¹³⁶Te	135.92010	17.5 s	^-	0+
¹³⁷Te	136.9253	2.5 s	^-; n	7/2-
¹³⁸Te	137.9292	1.4 s	^-
Discovered by Muller von Reichenstein in 1782; named by Klaproth, who isolated it in 1798. Tellurium is occasionally found native, but is more often found as the telluride of gold (calaverite - AuTe₂), and combined with other metals. It is recovered commercially from the anode muds produced during the electrolytic refining of blister copper. The U.S., Canada, Peru, and Japan are the largest Free World producers of the element. Crystalline tellurium has a silvery-white appearance, and when pure exhibits a metallic luster. It is brittle and easily pulverized. Amorphous tellurium is formed by precipitating tellurium from a solution of telluric or telturous acid. Whether this form is truly amorphous, or made of minute crystals, is open to question. Tellurium is a p-type semiconductor, and shows greater conductivity in certain directions, depending on alignment of the atoms. Its conductivity increases slightly with exposure to light. It can be doped with silver, copper, gold, tin, or other elements. In air, tellurium burns with a greenish-blue flame, forming the dioxide (TeO₂). Molten tellurium corrodes iron, copper, and stainless steel. Tellurium and its compounds are probably toxic and should be handled with care. Workmen exposed to as little as 0.01 mg/cu m of air, or less, develop "tellurium breath," which has a garlic-like odor. Forty-two isotopes and isomers of tellurium are known, with atomic masses ranging from 106 to 138. Natural tellurium consists of eight isotopes, two of which are radioactive with very long half-lives. Tellurium improves the machinability of copper and stainless steel, and its addition to lead decreases the corrosive action of sulfuric acid on lead and improves its strength and hardness. Tellurium is used as a basic ingredient in blasting caps, and is added to cast iron for chill control. Tellurium is used in ceramics. Bismuth telluride (Bi₂Te₃) has been used in thermoelectric devices. LINKS: AMM Online - Tellurium Profile Information, data sheet and standard forms Selenium Tellurium Development Association Tellurium Minerals Thermoelectrics - A Silent Cool USGS Minerals Information: Selenium and Tellurium Return Sources for the information on this website include: Lide, David R., ed. CRC Handbook of Chemistry and Physics, 78th Ed., 1997-1998.

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