All practice pages/Interatomic theory/Elements

52Te127.60

Element 52, a metalloid

Tellurium

One of the rarest stable elements in the crust, named for the Earth, and a key ingredient in thin-film solar panels.

At a glance

Symbol
Te
Atomic number
52
Average atomic mass
127.60
Group
16
Period
5
Family
metalloid
Electron configuration
[Kr] 4d¹⁰ 5s² 5p⁴
Valence electrons
6
Electronegativity
2.10
Common ions
Te²⁻ (telluride); +4 and +6 with oxygen

On the table

Periodic table with Tellurium highlighted123456789101112131415161718123456757-7189-103HHeLiBeBCNOFNeNaMgAlSiPSClArKCaScTiVCrMnFeCoNiCuZnGaGeAsSeBrKrRbSrYZrNbMoTcRuRhPdAgCdInSnSbTeIXeCsBaLaCePrNdPmSmEuGdTbDyHoErTmYbLuHfTaWReOsIrPtAuHgTlPbBiPoAtRnFrRaAcThPaUNpPuAmCmBkCfEsFmMdNoLrRfDbSgBhHsMtDsRgCnNhFlMcLvTsOg

Period 5, group 16. The other metalloids are tinted, and every cell opens its own article.

Electrons and bonding

Te

A metalloid: it tends to share electrons in covalent bonds rather than give them up completely.

Properties

State at 25 °C
solid
What it looks like
brittle, silvery-white metalloid
Melting point
449.5 °C
Boiling point
988 °C
Density
6.23 g/cm³

Where it is found

About as rare in the crust as gold and platinum. It turns up in gold ores as tellurides such as calaverite (AuTe₂), and it is recovered from the sludge left when copper is refined.

Discovery and name

Franz-Joseph Müller von Reichenstein found it in 1782 in a gold ore from Transylvania. Martin Heinrich Klaproth confirmed it in 1798 and named it from the Latin tellus, earth.

What it is used for

Cadmium telluride thin-film solar panels now take a large share. Bismuth telluride makes thermoelectric coolers and generators, tellurium alloys store data in rewritable optical discs, and small additions make steel and copper easier to machine and help cure rubber.

In compounds

CdTecadmium telluride, solar panelsBi₂Te₃bismuth telluride, thermoelectric coolersTeO₂tellurium dioxideAuTe₂calaverite, a gold oreH₂Tehydrogen telluride

Handle with care

Even small exposures give the breath and sweat a strong garlic smell for weeks, from a compound the body makes out of it. Larger amounts are toxic.