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Tellurium (Te)

Tellurium is a chemical element of the periodic table with chemical symbol Te and atomic number 52 with an atomic weight of 127.603 u and is classed as metalloid and is part of group 16 (oxygen group). Tellurium is solid at room temperature.

Tellurium in the periodic table

Atomic number52
Group16 (Oxygen group)
Color Silver
Number of protons52 p+
Number of neutrons76 n0
Number of electrons52 e-
From Wikipedia, the free encyclopediaTellurium is a chemical element with symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur.

Physical properties

Phase at STPSolid
Density6.24 g/cm3
Atomic weight127.603 u

Thermal properties

Melting point722.66 K
449.51 °C
841.118 °F
Boiling point1261 K
987.85 °C
1810.13 °F
Heat of vaporization50.63 kJ/mol

Atomic properties

Electronegativity (Pauling Scale)2.1
Electron affinity190.161 kJ/mol
Oxidation states−2, −1, +1, +2, +3, +4, +5, +6
(a mildly acidic oxide)
Ionization energies
  1. 869.3 kJ/mol
  2. 1790 kJ/mol
  3. 2698 kJ/mol
  4. 3610 kJ/mol
  5. 5668 kJ/mol
  6. 6820 kJ/mol
  7. 13200 kJ/mol

Electron configuration for tellurium

Electron configuration
Shorthand configuration
[Kr] 4d10 5s2 5p4
Electron configuration
Full configuration
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p4
Electron configuration chart
Electrons per shell2, 8, 18, 18, 6
Valence electrons 6
Valency electrons 2,4,6
Bohr model
TelluriumElectron shell for Tellurium, created by Injosoft ABTe
Figure: Shell diagram of Tellurium (Te) atom.
Orbital Diagram

The history of Tellurium

DiscoveryFranz-Joseph Müller von Reichenstein (1782)
First isolationMartin Heinrich Klaproth
Named byMartin Heinrich Klaproth (1798)
Discovery of tellurium
Tellurium (Latin tellus meaning "earth") was discovered in the 18th century in a gold ore from the mines in Kleinschlatten (today Zlatna), near today's city of Alba Iulia, Romania. In 1782 Franz-Joseph Müller von Reichenstein, who was then serving as the Austrian chief inspector of mines in Transylvania, concluded that the ore did not contain antimony but was bismuth sulfide. The following year, he reported that this was erroneous and that the ore contained mostly gold and an unknown metal very similar to antimony. After a thorough investigation that lasted three years and included more than fifty tests, Müller determined the specific gravity of the mineral and noted that when heated, the new metal gives off a white smoke with a radish-like odor; that it imparts a red color to sulfuric acid; and that when this solution is diluted with water, it has a black precipitate. Nevertheless, he was not able to identify this metal and gave it the names aurum paradoxum (paradoxical gold) and metallum problematicum (problem metal), because it did not exhibit the properties predicted for antimony. In 1789, a Hungarian scientist, Pál Kitaibel, discovered the element independently in an ore from Deutsch-Pilsen that had been regarded as argentiferous molybdenite, but later he gave the credit to Müller. In 1798, it was named by Martin Heinrich Klaproth, who had earlier isolated it from the mineral calaverite.


List of unique identifiers for Tellurium in various chemical registry databases
CAS Number13494-80-9
ChemSpider ID4885717
EC number236-813-4
PubChem CID Number6327182