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Definition: holmium from Philip's Encyclopedia

(symbol Ho) Metallic element of the lanthanide series (rare-earth metals), first identified spectroscopically in 1878 by Swiss chemists and in 1897 by Swedish chemist Per Cleve (1840-1905) who named it after the Latin name for Stockholm (Holmia). Its chief ore is monazite. The element has few commercial uses. Properties: at.no. 67; r.a.m. 164.9304; r.d. 8.795 (25°C); m.p. 1,474°C (2685°F); b.p. 2,695°C (4,883°F); most common isotope Ho165 (100%).


Summary Article: holmium
from The Columbia Encyclopedia

(hōl'mēəm) [Lat.,=Stockholm], metallic chemical element; symbol Ho; at. no. 67; at. wt. 164.93032; m.p. about 1,474 degrees Celsius; b.p. about 2,425 degrees Celsius; sp. gr. 8.78 at 25 degrees Celsius; valence +3. Holmium is a soft, malleable, lustrous, silvery metal of the lanthanide series in Group 3 of the periodic table. It is prepared by reduction of a holmium halide with calcium metal. Holmium is stable in dry air at room temperature but is rapidly oxidized in moist air or when heated. Holmia, the oxide, is found in nature, with other rare earths, in the minerals gadolinite and monazite. Holmium, its oxide, and its salts have no commercial uses. The metal was discovered spectroscopically in 1878 by the Swiss chemists Soret and Delafontaine and independently in 1879 by the Swedish chemist Per T. Cleve; it is named for Cleve's native city.

The Columbia Encyclopedia, © Columbia University Press 2017

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