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Terbium - Tb General Information Discovery Terbium was discovered by C.G. Mosander in 1843 in Stockholm, Sweden. Appearance Terbium is a silver-grey metal, malleable, ductile, and soft enough to be cut with a knife. Source Terbium can be recovered from the mineral monazite by ion exchange and solvent extraction, and from euxenite, a complex oxide containing 1% or more of terbium. It is usually produced commercially by reducing the anhydrous fluoride or chloride with calcium metal. Uses Terbium is used to dope calcium fluoride, calcium tungstate and strontium molybdate, all used in solid-state devices. Terbium salts are used in laser devices, but otherwise this element is not widely used. Biological Role Terbium has no known biological role, and has low toxicity. General Information Terbium is slowly oxidised by air, and reacts with cold water. |
| Physical Information | |||
| Atomic Number | 65 | ||
| Relative Atomic Mass (12C=12.000) | 158.92 | ||
| Melting Point/K | 1629 | ||
| Boiling Point/K | 3396 | ||
| Density/kg m-3 | 8229 (293K) | ||
| Ground State Electron Configuration | [Xe]4f96s2 | ||
| Electron Affinity(M-M-)/kJ mol-1 | -50 |
| Key Isotopes | ||||||
| nuclide | 159Tb | 160Tb | ||||
| atomic mass | 158.9 | |||||
| natural abundance | 100% | 0% | ||||
| half-life | stable | 72.1 days |
| Other Information | ||
| Enthalpy of Fusion/kJ mol-1 | 16.3 | |
| Enthalpy of Vaporisation/kJ mol-1 | 391 | |
| Oxidation States | ||
| Tb+3, Tb+4 | ||
| Ionisation Energies/kJ mol-1 | ||
| M - M+ | 564.6 | |
| M+ - M2+ | 1112 | |
| M2+ - M3+ | 2114 | |
| M3+ - M4+ | 3839 | |
| M4+ - M5+ | ||
| M5+ - M6+ | ||
| M6+ - M7+ | ||
| M7+ - M8+ | ||
| M8+ - M9+ | ||
| M9+ - M10+ | ||
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