Discovery date : 1861
Discovered by: Gustav Kirchhoff and Robert Bunsen
Origin of the name: The name is derived form the Latin 'rubidius', meaning deepest red.
Allotropes :
~>RUBIDIUM is a chemical element with symbol Rb and atomic number 37. Rubidium is a soft, silvery-white metallic element of the alkali metal group, with a standard atomic weight of 85.4678.
| FACT BOX | |||
| Group | 1 | Melting point | 39.30°C, 102.74°F, 312.45 K |
| Period | 5 | Boiling point | 688°C, 1270°F, 961 K |
| Block | s | Density (g cm−3) | 1.53 |
| Atomic number | 37 | Relative atomic mass | 85.468 |
| State at 20°C | Solid | Key isotopes | 85Rb,87Rb |
| Electron configuration | [Kr] 5s1 | CAS number | 7440-17-7 |
| ChemSpider ID | 4512975 | ChemSpider is a free chemical structure database | |
The lithium potassium mineral lepidolite was discovered in the 1760s and it behaved oddly. When thrown on to glowing coals it frothed and then hardened like glass. Analysis showed it to contain lithium and potassium, but it held a secret: rubidium.
In 1861, Robert Bunsen and Gustav Kirchhoff, of the University of Heidelberg, dissolved the ore in acid and then precipitated the potassium it contained which carried down another heavier alkali metal. By carefully washing this precipitate with boiling water they removed the more soluble potassium component and then confirmed that they really had a new element by examining the atomic spectrum of what remained. This showed two intense ruby red lines never seen before, indicating a new element, which they named after this colour.
A sample of pure rubidium metal was eventually produced in 1928.