cesium

ce·si·um also cae·si·um  (sz-m)

n. Symbol Cs

A soft, silvery-white ductile metal, liquid at room temperature, the most electropositive and alkaline of the elements, used in photoelectric cells and to catalyze hydrogenation of some organic compounds. Atomic number 55; atomic weight 132.905; melting point 28.5°C; boiling point 690°C; specific gravity 1.87; valence 1. See Table at element.

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[From Latin caesius, bluish gray (from its blue spectral lines).]

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cesium [ˈsiːzɪəm]

n

(Chemistry / Elements & Compounds) the usual US spelling of caesium

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cesium  (sz-m)

Symbol Cs

A soft, ductile, silvery-white element of the alkali group. It is liquid at room temperature and is the most reactive of all metals. Cesium is used to make photoelectric cells, electron tubes, and atomic clocks. Atomic number 55; atomic weight 132.905; melting point 28.5°C; boiling point 690°C; specific gravity 1.87; valence 1. See Periodic Table.

Thesaurus

Noun

1.

cesium - a soft silver-white ductile metallic element (liquid at normal temperatures); the most electropositive and alkaline metal atomic number 55, caesium, Cs metal, metallic element - any of several chemical elements that are usually shiny solids that conduct heat or electricity and can be formed into sheets etc. cesium 137 - a radioactive isotope of cesium used in radiation therapy pollucite - a rare mineral that is an important source of cesium