caesium

(US), cesium

a ductile silvery-white element of the alkali metal group that is the most electropositive metal. It occurs in pollucite and lepidolite and is used in photocells. The radioisotope caesium-137, with a half-life of 30.2 years, is used in radiotherapy. Symbol: Cs; atomic no.: 55; atomic wt.: 132.90543; valency: 1; relative density: 1.873; melting pt.: 28.39±0.01°C; boiling pt.: 671°C

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

Mentioned in

A-1 time
Accumulation of Radioactive Substances in the Biosphere
Alkali Metal
antimony pentachloride
antishock agent
atomic clock
atomic second
atomic time
atomic-beam frequency standard
beryl
Brine, Underground
Bunsen
Bunsen, Robert Wilhelm von
Cesium
cesium bromide
cesium carbonate
cesium chloride
cesium electron tube
cesium fluoride

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