ElementsWhat is tellurium?
Tellurium is a silvery-white, brittle element. It is one of the rarest stable elements in the Earth's crust.
What is tellurium used for?
Thin-film solar panels, alloys that are easier to machine, and rewritable optical discs.
Where the name comes from
From the Latin word tellus, the Earth.
Key facts
- Symbol
- Te
- Atomic number
- 52
- Atomic mass
- 127.6 u
- Family
- Metalloid
- Period
- 5
- Group
- 16
- Block
- p
- State at room temperature
- Solid
- Melting point
- 449.5 °C (722.66 K, 841 °F)
- Boiling point
- 987.9 °C (1,261 K, 1,810 °F)
- Density
- 6.23 g/cm³
- Electrons per shell
- 2, 8, 18, 18, 6
- Electron configuration
- [Kr]5s2 4d10 5p4
- Common oxidation states
- +6, +4, -2
- Electronegativity (Pauling)
- 2.1
- First ionisation energy
- 9.01 eV
- Electron affinity
- 1.971 eV
- Atomic radius (van der Waals)
- 206 pm
- Discovered
- 1782
Place in the periodic table
Tellurium is element number 52. It sits in period 5 (row 5) of the periodic table, in group 16 (column 16), and belongs to the p-block. Just before it comes antimony (51), and just after it comes iodine (53). In the same column, selenium is above it and polonium is below it. Elements in one column tend to behave alike.
Family: Metalloids.
Physical properties
At room temperature tellurium is a solid. It melts at 449.5 °C and boils at 987.9 °C, so it stays liquid over a range of 538 degrees. Its density is 6.23 grams per cubic centimetre, so a one-litre block would weigh about 6.23 kilograms. By density it ranks 56th among the 96 elements with a measured value.
Inside the atom
An atom of tellurium has 52 protons in its nucleus and, when neutral, 52 electrons around it. The electrons are arranged in 5 shells: 2, 8, 18, 18, 6. The outermost shell holds 6 electrons. Written in full, the electron configuration is [Kr]5s2 4d10 5p4.
Its electronegativity on the Pauling scale is 2.1. This number shows how strongly an atom pulls shared electrons towards itself: fluorine, the strongest, is 3.98. Removing one electron from an atom takes 9.01 electronvolts (about 869 kilojoules per mole). One mole of tellurium weighs 127.6 grams, so a single gram contains about 4.72 × 1021 atoms.
The ring picture is a simple model that only counts the electrons in each shell. Real atoms do not look like this.
Next steps
- Work out the weight of a compound that contains tellurium with the molar mass calculator.
- Compare it with every other element in the sortable list.
- Test yourself with the symbol quiz.
Figures on this page are from PubChem (U.S. National Library of Medicine), as downloaded on 11 November 2026. See About and data sources.