Tellurium
metalloidProperties
| Property | Value |
|---|---|
| Atomic Mass | 127.6 amu |
| Category | metalloid |
| Group | 16 |
| Period | 5 |
| Electron Configuration | 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p4 |
| Electronegativity | 2.1 (Pauling) |
| Oxidation States | 4, 6, 2, -2 |
| Melting Point | 722.66 K (449.5 °C) |
| Boiling Point | 1261 K (987.9 °C) |
| Density | 6.24 g/cm³ |
| Discovered By | Franz-Joseph Muller von Reichenstein (1783) |
About Tellurium
Tellurium is one of the rarest stable elements in the crust — about as scarce as platinum — and almost every gram of it produced today comes out of the anode slimes left over after copper electrorefining. Sitting below selenium in group 16, it's a brittle silver-grey metalloid that you can grind to powder and that conducts a little better when you shine light on it. That photoconductivity, plus a near-ideal 1.45 eV bandgap when paired with cadmium, is what made CdTe thin-film panels (the technology First Solar built its business on) the cheapest utility-scale photovoltaic per watt for years. Te also shows up in Bi₂Te₃ Peltier coolers — the modules in wine fridges and CCD camera coolers — and in GeSbTe phase-change films, where the reversible amorphous-to-crystalline switch is what stores a bit in rewritable Blu-rays and Intel's Optane memory. The garlic-breath warning is real: even microgram exposures convert to dimethyl telluride, which exhales for weeks.
Fun Fact
Exposure to even trace amounts of tellurium causes a persistent garlic-like odor in a person's breath and sweat that can last for weeks, caused by the body converting tellurium into dimethyl telluride, making tellurium workers easily identifiable.
Common Uses
- CdTe absorber layers in First Solar utility-scale thin-film panels
- Bi₂Te₃ thermoelectric legs for Peltier coolers and CPU spot-cooling
- Ge₂Sb₂Te₅ phase-change films in rewritable optical discs and 3D XPoint memory
- Free-machining additive (~0.5 wt%) in 12L14 leaded steel and tellurium-copper
- Vulcanization accelerator that raises the heat resistance of tire and belt rubber
- ZnTe and CdZnTe room-temperature gamma detectors for portable radiation monitors