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Thulium - Tm General Information Discovery Thulium was discovered by P.T. Cleve in 1879 in Uppsala, Sweden. Appearance Thulium is a silvery metal with a bright lustre. Source Thulium is found principally in the mineral monazite, from which it is extracted by ion exchange and solvent extraction. It can also be isolated by reduction of the anhydrous fluoride with calcium metal, or reduction of the oxide with lanthanum metal. Uses When irradiated in a nuclear reactor, thulium produces an isotope that emits X-rays. A "button" of this isotope is used to make a lightweight, portable X-ray machine for medical use. The "hot" thulium is replaced every few months. Otherwise this element is little used. Biological Role Thulium has no known biological role, and is non-toxic. General Information Thulium tarnishes in air and reacts with water. It is soft, malleable and ductile, and can be cut with a knife. |
| Physical Information | |||
| Atomic Number | 69 | ||
| Relative Atomic Mass (12C=12.000) | 168.93 | ||
| Melting Point/K | 1818 | ||
| Boiling Point/K | 2220 | ||
| Density/kg m-3 | 9321 (293K) | ||
| Ground State Electron Configuration | [Xe]4f136s2 | ||
| Electron Affinity(M-M-)/kJ mol-1 | 50 |
| Key Isotopes | ||||||
| nuclide | 169Tm | 170Tm | ||||
| atomic mass | 168.9 | |||||
| natural abundance | 100% | 0% | ||||
| half-life | stable | 134 days |
| Other Information | ||
| Enthalpy of Fusion/kJ mol-1 | 18.4 | |
| Enthalpy of Vaporisation/kJ mol-1 | 247 | |
| Oxidation States | ||
| main | TmIII | |
| others | TmII | |
| Covalent Bonds /kJ mol-1 | ||
| not applicable | ||
| Ionisation Energies/kJ mol-1 | ||
| M - M+ | 596.7 | |
| M+ - M2+ | 1163 | |
| M2+ - M3+ | 2285 | |
| M3+ - M4+ | 4119 | |
| M4+ - M5+ | ||
| M5+ - M6+ | ||
| M6+ - M7+ | ||
| M7+ - M8+ | ||
| M8+ - M9+ | ||
| M9+ - M10+ | ||
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