| Tecken | Te |
| Atomnummer | 52 |
| Grupp | 16 (Syregruppen) |
| Period | 5 |
| Block | p |
| Ämnesklass | Halvmetall |
| Utseende | - |
| Färg | Silver |
| Antal protoner | 52 p+ |
| Antal neutroner | 76 n0 |
| Antal elektroner | 52 e- |
| Fas vid STP | Fast |
| Densitet | 6.24 g/cm3 |
| Relativ atommassa | 127.603 u |
| Smältpunkt | 722.66 K 449.51 °C 841.118 °F |
| Kokpunkt | 1261 K 987.85 °C 1810.13 °F |
| Ångbildningsvärme | 50.63 kJ/mol |
| Elektronegativitet (Paulingskalan) | 2.1 |
| Elektronaffinitet | 190.161 kJ/mol |
| Oxidationstal | −2, −1, +1, +2, +3, +4, +5, +6 (a mildly acidic oxide) |
| Jonisationspotential |
|
| Upptäckt | Franz-Joseph Müller von Reichenstein (1782) |
| Första isolation | Martin Heinrich Klaproth |
| Namngivare | Martin Heinrich Klaproth (1798) |
Upptäckten av tellur 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. | |