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History and Production
Named after Homia, Latin word for Stockholm. It was discovered by J.-L. Soret and M. Delafontaine by spectroscopic means. It was independently discovered by P.T. Cleve in 1879 who separated chemically from erbium and thulium. The element was
subsequently named after Cleve's native city. It is now recovered mainly from monazite, a mixture of rare earth phosphates containing about 0.05% of the metal. Ion-exchange and solvent extraction techniques are used to isolate the salt and the metal is obtained by reduction of the
fluoride (HoF3) with calcium. At present time, the use of the element is limited. It is used as a component for some electronic device and as a catalyst for ortho-para hydrogen conversion.
Physical Data
It is a bright silver metal, relatively soft and malleable. It is one of the most paramagnetic substance ever known. Holmium usually exists along with other rare earth metals in gadolinite and monazite and with a natural abundance of about 1.4 ppm of the earth's crust.
Interatomic distance: 348.6 pm
Melting point: 1474°C
Boiling point: 2700°C
Thermal conductivity/Wm-1K-1: 16.2 (27°C)
Density/kgm-3: 8795 (20°C)
Standard Thermodynamic Data (atomic gas)
Enthalpy of formation: 300.8 kJ/mol
Gibbs free energy of formation: 264.8 kJ/mol
Entropy: 195.6 J/mol K
Heat capacity: 20.8 J/mol K
Electronic data
Electronic configuration: [Xe] 4f11 6s2
Term symbol: 4I5/2
Electron affinity: - Electronegativity (Pauline): 1.23
Ionization energy (first, second, third): 580.987, 1138.53, 2203.73 kJ/mol
Chemical properties
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