Discovery date : 1803
Discovered by: Smithson Tennant
Origin of the name: The name is derived from the Greek word 'osme', meaning smell.
Allotropes :
~>OSMIUM is a chemical element with symbol Os and atomic number 76. It is a hard, brittle, bluish-white transition metal in the platinum group that is found as a trace element in alloys, mostly in platinum ores. Osmium is the densest naturally occurring element, with a density of 700422590000000000022.59 g/cm^3.
| FACT BOX | |||
| Group | 8 | Melting point | 3033°C, 5491°F, 3306 K |
| Period | 6 | Boiling point | 5008°C, 9046°F, 5281 K |
| Block | d | Density (g cm−3) | 22.5872 |
| Atomic number | 76 | Relative atomic mass | 190.23 |
| State at 20°C | Solid | Key isotopes | 192Os |
| Electron configuration | [Xe] 4f145d66s2 | CAS number | 7440-04-2 |
| ChemSpider ID | 22379 | ChemSpider is a free chemical structure database | |
In 1803, Smithson Tennant added platinum to dilute aqua regia, which is a mixture of nitric and hydrochloric acids, and observed that not all the metal went into solution. Earlier experimenters had assumed that the residue was graphite, but he suspected it was something else, and he began to investigate it. By a combination of acid and alkali treatments he eventually separated it into two new metal elements, which he named iridium and osmium, naming the latter on account of the strong odour it gave off. Its name is derived from osme the Greek word for smell. Although it was recognised as a new metal, little use was made of it because it was rare and difficult to work with, although it was extremely hard wearing and for several years it was used for pen nibs and gramophone needles.