Discovery date : 1875
Discovered by: Paul-Émile Lecoq de Boisbaudran
Origin of the name: The name is derived from the Latin name for France, 'Gallia'
Allotropes :
~>GALLIUM is a chemical element with symbol Ga and atomic number 31. It is in group 13 of the periodic table, and thus has similarities to the other metals of the group, aluminium, indium, and thallium. Gallium does not occur as a free element in nature, but as gallium(III) compounds in trace amounts in zinc ores and in bauxite.
| FACT BOX | |||
| Group | 13 | Melting point | 29.7646°C, 85.5763°F, 302.9146 K |
| Period | 4 | Boiling point | 2229°C, 4044°F, 2502 K |
| Block | d | Density (g cm−3) | 5.91 |
| Atomic number | 31 | Relative atomic mass | 69.723 |
| State at 20°C | Solid | Key isotopes | 69Ga |
| Electron configuration | [Ar] 3d104s24p1 | CAS number | 7440-55-3 |
| ChemSpider ID | 4514603 | ChemSpider is a free chemical structure database | |
Gallium was discovered in Paris by Paul-Émile Lecoq de Boisbaudran in 1875. He observed a new violet line in the atomic spectrum of some zinc he had extracted from a sample of zinc blende ore (ZnS) from the Pyrenees. He knew it meant that an unknown element was present.
What Boisbaudran didn’t realise was that its existence, and properties, had been predicted by Mendeleev whose periodic table showed there was a gap below aluminium which was yet to be occupied. He forecast that the missing element’s atomic weight would be around 68 and its density would be 5.9 g/cm3.
By November of 1875, Boisbaudran had isolated and purified the new metal and shown that it was like aluminium. In December 1875 he announced it to the French Academy of Sciences.