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It's Elemental

The Element Tellurium

[Click for Isotope Data]


52 Te Tellurium 127.60

Atomic Number: 52

Atomic Weight: 127.60

Melting Point: 722.66 K (449.51°C or 841.12°F)

Boiling Point: 1261 K (988°C or 1810°F)

Density: 6.232 grams per cubic centimeter

Phase at Room Temperature: Solid

Element Classification: Semi-metal

Period Number: 5

Group Number: 16

Group Name: Chalcogen

What's in a name? From the Latin word for earth, tellus.

Say what? Tellurium is pronounced as te-LOOR-ee-em.

History and Uses:

Tellurium was discovered by Franz Joseph Müller von Reichenstein, a Romanian mining official, in 1782. Reichenstein was the chief inspector of all mines, smelters and saltworks in Transylvania. He also had an interest in chemistry and extracted a new metal from an ore of gold, known as aurum album, which he believed was antimony. He shortly realized that the metal he had produced wasn't antimony at all, but a previously unknown element. Reichenstein's work was forgotten until 1798 when Martin Heinrich Klaproth, a German chemist, mentioned the substance in a paper. Klaproth named the new element tellurium but gave full credit for its discovery to Reichenstein. Tellurium is found free in nature, but is most often found in the ores sylvanite (AgAuTe4), calaverite (AuTe2) and krennerite (AuTe2). Today, most tellurium is obtained as a byproduct of mining and refining copper.

Tellurium is a semiconductor and is frequently doped with copper, tin, gold or silver. Tellurium is also used to color glass and ceramics and is one of the primary ingredients in blasting caps.

Tellurium is primarily used as an alloying agent. Small amounts of tellurium are added to copper and stainless steel to make them easier to machine and mill. Tellurium is also added to lead to increase its strength and resistance to sulfuric acid (H2SO4).

Tellurium forms many compounds, but none that are commercially important. They include: tellourous acid (H2TeO2), tellurium tetrachloride (TeCl4), tellurium dichloride (TeCl2), tellurium trioxide (TeO3), tellurium monoxide (TeO) and sodium telluride (Na2Te).

Estimated Crustal Abundance: 1×10-3 milligrams per kilogram

Estimated Oceanic Abundance: Not Applicable

Number of Stable Isotopes: 5 (View all isotope data)

Ionization Energy: 9.010 eV

Oxidation States: +6, +4, -2

Electron Shell Configuration:


2s2   2p6

3s2   3p6   3d10

4s2   4p6   4d10

5s2   5p4

Citation and linking information

For questions about this page, please contact Steve Gagnon.