Tecken | Mo |
Atomnummer | 42 |
Grupp | 6 (Kromgruppen) |
Period | 5 |
Block | d |
Ämnesklass | Övergångsmetall |
Utseende | Gray metallic |
Färg | Grå |
Antal protoner | 42 p+ |
Antal neutroner | 54 n0 |
Antal elektroner | 42 e- |
Fas vid STP | Fast |
Densitet | 10.28 g/cm3 |
Relativ atommassa | 95.951 u |
Smältpunkt | 2896 K 2622.85 °C 4753.13 °F |
Kokpunkt | 4912 K 4638.85 °C 8381.93 °F |
Ångbildningsvärme | 590.4 kJ/mol |
Elektronegativitet (Paulingskalan) | 2.16 |
Elektronaffinitet | 72.1 kJ/mol |
Oxidationstal | −4, −2, −1, 0, +1, +2, +3, +4, +5, +6 (a strongly acidic oxide) |
Jonisationspotential |
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Upptäckt | Carl Wilhelm Scheele (1778) |
Första isolation | Peter Jacob Hjelm (1781) |
Upptäckten av molybden Molybdenite—the principal ore from which molybdenum is now extracted—was previously known as molybdena. Molybdena was confused with and often utilized as though it were graphite. Like graphite, molybdenite can be used to blacken a surface or as a solid lubricant. Although (reportedly) molybdenum was deliberately alloyed with steel in one 14th-century Japanese sword (mfd. ca. 1330), that art was never employed widely and was later lost. In the West in 1754, Bengt Andersson Qvist examined a sample of molybdenite and determined that it did not contain lead and thus was not galena. By 1778 Swedish chemist Carl Wilhelm Scheele stated firmly that molybdena was (indeed) neither galena nor graphite. Instead, Scheele correctly proposed that molybdena was an ore of a distinct new element, named molybdenum for the mineral in which it resided, and from which it might be isolated. Peter Jacob Hjelm successfully isolated molybdenum using carbon and linseed oil in 1781. |