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Holmium - Ho General Information Discovery The spectral absorption bands of holmium were first identified by M. Delafontaine and J.L. Soret in 1878 in Geneva, Switzerland. The element was independently discovered by P.T. Cleve in 1878 in Uppsala, Sweden. Appearance Holmium is a silvery metal with a bright lustre. Source The principal source of holmium is the mineral monazite, from which it is obtained by ion exchange and solvent extraction. It can also be obtained by reduction of the anhydrous fluoride by calcium metal. Uses Holmium can absorb fission-bred neutrons, so is used in nuclear reactors to keep a chain reaction under control. It is little used otherwise. Biological Role Holmium has no known biological role, and is non-toxic. General Information Holmium is relatively soft and malleable. It is slowly attacked by water and oxygen, and reacts with acid. |
| Physical Information | |||
| Atomic Number | 67 | ||
| Relative Atomic Mass (12C=12.000) | 164.93 | ||
| Melting Point/K | 1747 | ||
| Boiling Point/K | 2968 | ||
| Density/kg m-3 | 8795 (298K) | ||
| Ground State Electron Configuration | [Xe]4f116s2 | ||
| Electron Affinity(M-M-)/kJ mol-1 | -50 |
| Key Isotopes | ||||||
| nuclide | 165Ho | 166Ho | ||||
| atomic mass | 164.9 | |||||
| natural abundance | 100% | 0% | ||||
| half-life | stable | 26.9 h |
| Other Information | ||
| Enthalpy of Fusion/kJ mol-1 | 17.2 | |
| Enthalpy of Vaporisation/kJ mol-1 | 303 | |
| Oxidation States | ||
| Ho+3 | ||
| Ionisation Energies/kJ mol-1 | ||
| M - M+ | 580.7 | |
| M+ - M2+ | 1139 | |
| M2+ - M3+ | 2204 | |
| M3+ - M4+ | 4100 | |
| M4+ - M5+ | ||
| M5+ - M6+ | ||
| M6+ - M7+ | ||
| M7+ - M8+ | ||
| M8+ - M9+ | ||
| M9+ - M10+ | ||
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