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Scandium - Sc General Information Discovery Scandium was discovered by L.F. Nilson in 1879 in Uppsala, Sweden. It was, however, predicted by Mendeleev who named it ekaboron. Appearance Scandium is a soft, silvery-white metal, which becomes slightly tinged with yellow or pink upon exposure to the air. Source Scandium is the 50th most abundant element on the Earth. It is very widely distributed, and occurs in minute quantities in over 800 mineral species. In the rare mineral thortveitite, however, which is found in Scandinavia, it is the principal component. Scandium can be recovered from thortveitite or extracted as a by-product from uranium mill tailings. Metallic scandium can also be prepared by electrolysing a eutectic melt of potassium, lithium and scandium chlorides, with electrodes of tungsten wire and a pool of molten zinc. Uses Scandium is not widely used. Scandium iodide is added to mercury vapour lamps to produce a highly efficient light source resembling sunlight, which is important for indoor lighting and night-time colour television screens. The radioactive isotope 46Sc is used as a tracing agent in refinery crackers for crude oil. However, the potential for scandium is great because it has almost as low a density as aluminium and has a much higher melting point, so it has attracted the interest of spacecraft designers. Biological Role Scandium has no known biological role, but is a suspected carcinogen. General Information Scandium is a much more abundant element in the Sun and in certain stars than here on Earth. The blue colour of beryl (the aquamarine variety) is attributed to scandium. |
| Physical Information | |||
| Atomic Number | 21 | ||
| Relative Atomic Mass (12C=12.000) | 44.956 | ||
| Melting Point/K | 1814 | ||
| Boiling Point/K | 3104 | ||
| Density/kg m-3 | 2989 (273K) | ||
| Ground State Electron Configuration | [Ar]3d14s2 | ||
| Electron Affinity(M-M-)/kJ mol-1 | +70 |
| Key Isotopes | ||||||
| nuclide | 44Sc | 45Sc | 46Sc | 47Sc | ||
| atomic mass | 44.956 | 45.955 | ||||
| natural abundance | 0% | 100% | 0% | 0% | ||
| half-life | 3.92 h | stable | 83.80 days | 3.34 days |
| Other Information | ||
| Enthalpy of Fusion/kJ mol-1 | 15.9 | |
| Enthalpy of Vaporisation/kJ mol-1 | 376.1 | |
| Oxidation States | ||
| Sc+2, Sc+3 | ||
| Ionisation Energies/kJ mol-1 | ||
| M - M+ | 631 | |
| M+ - M2+ | 1235 | |
| M2+ - M3+ | 2389 | |
| M3+ - M4+ | 7089 | |
| M4+ - M5+ | 8844 | |
| M5+ - M6+ | 10720 | |
| M6+ - M7+ | 13320 | |
| M7+ - M8+ | 15310 | |
| M8+ - M9+ | 17369 | |
| M9+ - M10+ | 21740 | |
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