Discovery date : 1781
Discovered by: Peter Jacob Hjelm
Origin of the name: The name is derived from the Greek 'molybdos' meaning lead.
Allotropes :
~>MOLYBDENUM is a chemical element with symbol Mo and atomic number 42. The name is from Neo-Latin molybdaenum, from Ancient Greek molybdos, meaning lead, since its ores were confused with lead ores.
| FACT BOX | |||
| Group | 6 | Melting point | 2622°C, 4752°F, 2895 K |
| Period | 5 | Boiling point | 4639°C, 8382°F, 4912 K |
| Block | d | Density (g cm−3) | 10.2 |
| Atomic number | 42 | Relative atomic mass | 95.95 |
| State at 20°C | Solid | Key isotopes | 95Mo,96Mo,98 |
| Electron configuration | [Kr] 4d55s1 | CAS number | 7439-98-7 |
| ChemSpider ID | 22374 | ChemSpider is a free chemical structure database | |
The soft black mineral molybdenite (molybdenum sulfide, MoS2), looks very like graphite and was assumed to be a lead ore until 1778 when Carl Scheele analysed it and showed it was neither lead nor graphite, although he didn’t identify it.
Others speculated that it contained a new element but it proved difficult to reduce it to a metal. It could be converted to an oxide which, when added to water, formed an acid we now know as molybdic acid, H2MoO4, but the metal itself remained elusive.
Scheele passed the problem over to Peter Jacob Hjelm. He ground molybdic acid and carbon together in linseed oil to form a paste, heated this to red heat in and produced molybdenum metal. The new element was announced in the autumn of 1781.