| MANGANESE | (sub>25Mn |
|---|---|
| Appearance | Manganese is a grey-white metal that resembles iron. It is harder than iron and very brittle. |
| Discovery | It was recognised as an element by Scheele, Bergman and others. It was isolated in 1774 by J. G. Grahn in Stockholm, Sweden. |
| Electronic Configuration | simple: 2.8.13.2 ADVANCED: 1s2 2s2 2p6 3s2 3p6 3d5 4s2 or [Ar] 3d5 4s2 for short. |
| Isotopes | 53Mn has a half-life of 2 x 106 years; 54Mn has a half-life of 303 days; 55Mn as an abundance of 100% and 56Mn has a half-life of just 2.576 hours. |
| Source | Manganese minerals are widely distributed. Pyrolusite and rhodochrosite are the most common. Nodules of manganese have been found on the floor of oceans. These contain about 24% manganese, together with many other elements, in lesser abundance. |
| Common uses | Manganese is used to make many important alloys. It gives steel a hard, yet pliant quality. With aluminium and antimony it forms highly ferromagnetic alloys. Manganese(IV) oxide is used as a depolariser in dry cells, and to decolouris glass, coloured green by iron impurities. Manganese(II) oxide is a powerful oxidising agent, and is used in quantitative analysis, and in medicine. |
| Test | - |
| Melting point in Kelvin | 1517 |
| Boiling point in Kelvin | 2235 |
| Density in kg/m3 | 7440 at 293K |
| Oxidation States | -3 -2 -1 0 +1 +2 +3 +4 +5 +6 and +7 but mostly as +2 |
| IE1 in kJmol-1 | 717.4 |
| IE2 in kJmol-1 | 1509.0 |
| IE3 in kJmol-1 | 3248.4 |
| IE4 in kJmol-1 | 4940 |
| IE5 in kJmol-1 | 6990 |
| IE6 in kJmol-1 | 9200 |
| IE7 in kJmol-1 | 11508 |
| IE8 in kJmol-1 | 18956 |
| IE9 in kJmol-1 | 21400 |
| IE10 in kJmol-1 | 23960 |
| EA1 in kJmol-1 | -94 |
| Enthalpy of Fusion in kJmol-1 | 14.4 |
| Enthalpy of Vaporisation in kJmol-1 | 220.5 |