Tellurium is one of the 10 rarest elements on this planet. It gets its name from the Latin word tellus, meaning earth. This element is often found as a compound with another element, such as metallic nickel, as in the case of the mineral melonite. Tellurium is also produced as a waste product when lead and copper are refined. Pure tellurium can take two forms: a shiny metallic solid or a brown powder. This element is mainly used in fiber optic glass.
Summary of properties (Te)
| Atomic weight | 127.60(3) |
| Discoverer (year) | Müller von Reichenstein, Franz Joseph (1782) |
| Natural form | non-metal solid (hexagonal) |
| Electron configuration | [Kr] 4d10 5s2 5p4 |
| Melting point (ºC) | 449 |
| Boiling point (ºC) | 990 |
| Abundance in earth's crust (ppm) | 0.001 |
| Isotope (abundance) | 120Te (0.09), 122Te (2.55), 123Te (0.89), 124Te (4.74), 125Te (7.07), 126Te (18.84), 128Te (31.74), 130Te (34.08) |
| Density g/cm3 | 4.93 |
| Van der Waals radius (pm) | 206 |
| Covalent radius (pm) | 137 |
| Electronegativity (Pauling) | 2.1 |
| Vaporization enthalpy (kJ/mol) | 114.10 |
| Enthalpy of fusion (kJ/mol) | 17.49 |
| Specific heat capacity (J/g·K) at 25ºC and 1 atm | 0.20 |
| Thermal conductivity (W/cm·K) at 25ºC and 1 atm | 0.030 |
| Oxidation state | +6, +4, -2 |
| Electron affinity (eV) | 1.97 |
| 1st Ionization potential (eV) | 9.0096 |
