Tellurium
Element 52 · Metalloid
Tellurium is a brittle, silvery-white metalloid in group 16 with semiconductor properties that make it valuable in clean-energy technology: cadmium telluride is the light-absorbing layer in one of the cheapest types of solar panel, and tellurium compounds convert heat directly into electricity in thermoelectric devices. It is chemically similar to sulfur and selenium but far rarer. Tellurium is also famous for an odd biological quirk — the body converts absorbed tellurium into volatile compounds exhaled on the breath, giving workers a persistent garlic odor after even minor exposure.
Key facts
| Atomic number | 52 |
|---|---|
| Atomic weight | 127.60 |
| Category | Metalloid |
| Group / Period | 16 / 5 |
| Block | p |
| Electron configuration | [Kr] 4d10 5s2 5p4 |
| Common oxidation states | +4, +6, -2 |
| State at STP | Solid |
| Electronegativity | 2.1 |
| Atomic radius | 123 pm (empirical) |
| Density | 6.24 g/cm³ |
| Melting point | 449.51 °C |
| Boiling point | 988 °C |
Occurrence
Tellurium is one of the scarcest stable elements in Earth's crust, rarer than platinum. It is recovered mainly as a by-product of copper refining, from the slimes left after copper electrolysis.
Applications
Cadmium telluride solar panels
Thermoelectric cooling devices
Rewritable optical discs
Steel and copper alloys
Common compounds
- Tellurium dioxide
- Cadmium telluride
- Hydrogen telluride
Tellurium is one of the rarest stable elements in Earth's crust — and exposure to even tiny amounts gives a person's breath a strong garlic smell for weeks.
Data source: IUPAC standard atomic weights 2021; NIST physical property data