Tellurium

Background

caption This sample of tellurium is displayed in the Smithsonian Museum of Natural History. The sample is about 6x4 cm and is from the De La Mar mine, Delamar, Nevada. (Source: Georgia State University)

Tellurium is a metallic, silvery-white element. Some even describe its appearance as "very metallic." Its atomic number is 52 and its symbol is Te. It was discovered in 1783 by Baron Franz Joseph Muller von Reichenstein of Romania, the chief inspector of mines in Transylvania at the time. Tellurium is very brittle and easily pulverized. It does not react with air or water.

As a commodity, tellurium is used in industry as pure tellurium metal, tellurium dioxide (TeO2), and alloyed (that is, mixed) with other metals.

Tellurium has no known benefit to humans. It does have a strange effect on humans, though. When tellurium is ingested, even in very small amounts, it causes very bad, garlic-smelling breath and body odor.

There are a very small number of tellurium minerals. It combines with oxygen to form tellurite, and with gold and silver to form sylvanite (Au,Ag)Te2. The most common gold telluride mineral is called calaverite (AuTe2).

Name

Previous Element: Antimony

Next Element: Iodine
52

Te

127.6
Physical Properties
Color Silvery
Phase at Room Temp. solid
Density (g/cm3) 6.25
Hardness (Mohs) 2.3
Melting Point (K) 722.7
Boiling Point (K) 1263
Heat of Fusion (kJ/mol) 13.5
Heat of Vaporization (kJ/mol) ---
Heat of Atomization (kJ/mol) 197
Thermal Conductivity (J/m sec K) 11.54
Electrical Conductivity (1/mohm cm) 0
Source Zn/Pb smelting by-product
Atomic Properties
Electron Configuration [Kr]4d105s25p4
Number of Isotopes 8
Electron Affinity (kJ/mol) 190.16
First Ionization Energy (kJ/mol) 869.2
Second Ionization Energy (kJ/mol) 1794.6
Third Ionization Energy (kJ/mol) 2697.7
Electronegativity 2.1
Polarizability (Å3) 5.5
Atomic Weight 127.6
Atomic Volume (cm3/mol) 20.4
Ionic Radius2- (pm) 207
Ionic Radius1- (pm) ---
Atomic Radius (pm) 142
Ionic Radius1+ (pm) ---
Ionic Radius2+ (pm) ---
Ionic Radius3+ (pm) ---
Common Oxidation Numbers -2,+2,+4,+6
Other Oxid. Numbers +5
Abundance
In Earth's Crust (mg/kg) 1×10-3
In Earth's Ocean (mg/L) No data available
In Human Body (%) near 0%
Regulatory / Health
CAS Number 13494-80-9
OSHA Permissible Exposure Limit (PEL) TWA: 0.1 mg/m3
OSHA PEL Vacated 1989 TWA: 0.1 mg/m3
NIOSH Recommended Exposure Limit (REL) TWA: 0.1 mg/m3
IDLH: 25 mg/m3
Sources:
University of Wisconsin General Chemistry
Mineral Information Institute
Jefferson Accelerator Laboratory
EnvironmentalChemistry.com
 

The name tellurium came from the Latin word tellus meaning earth.

Sources

Tellurium is recovered from the residue produced in refining blister copper from deposits containing recoverable amounts of tellurium. There are large quantities of tellurium in some gold and lead deposits, but the tellurium is not being recovered from these at this time. In addition, tellurium is present in coal and some lower-grade copper deposits, but the cost of recovering the tellurium from these deposits is too high to make it worth the effort. These deposits are called subeconomic deposits.

Nations producing tellurium and tellurium dioxide are the United States, Canada, Japan, Peru, and a number of other countries. As with most commodities, companies in the United States import tellurium. Of the tellurium imported each year, most comes from the United Kingdom, followed by Philippines, Belgium, Canada, and a number of other nations.

Uses

Half of the tellurium consumed each year is used to improve the machinability of special iron and steel products. It is alloyed with copper to make copper more ductile (that is, easier to stretch into wires), and with lead to prevent corrosion. These, and other nonferrous tellurium alloys, account for approximately 10% of tellurium use. Tellurium is also used to make catalysts and chemicals. Some of these chemicals are used in the petroleum industry and in making rubber. Tellurium is added to selenium-based photoreceptors to broaden the spectral range of copiers. Tellurium is also used in other electronic applications, and in the production of blasting caps for explosives.

Substitutes and Alternative Sources

Selenium, bismuth and lead can be used in place of tellurium in many of its metallurgical uses. Selenium and sulfur can be used in place of tellurium in the production of rubber.

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Glossary

Citation

Institute, M. (2008). Tellurium. Retrieved from http://www.eoearth.org/view/article/156462

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