caesium

xenon$\longleftarrow$ 55 $\longrightarrow$barium

Other spellings

• cesium

Pronunciation

• enPR: sē'zēəm, IPA ^(key): /ˈsiːziəm/, SAMPA: /"si:zi@m/

• Audio (US)

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Noun

Singular caesium

Plural none

Caesium.

1. (uncountable) Caesium is a chemical element that is a very soft silver-gold coloured alkali metal with the atomic number 55 and the symbol Cs.

   The atomic clock uses caesium to keep accurate time.