cesium

or cae·si·um

[ see-zee-uhm ]

Phonetic (Standard)IPA

noun

a rare, highly reactive, soft, metallic element of the alkali metal group, used chiefly in photoelectric cells. : Cs; : 132.905; : 55; : 1.9 at 20°C; melts at 28.5°C.

cesium

/ ˈsiːzɪəm /

cesium

/ sē′zē-əm /

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

Origin of cesium¹

1930–35; < New Latin, special use of Latin caesium, neuter of caesius bluish-grey; -ium

The levels of radioactive cesium and potassium were elevated, and the source was unmistakable.

Even at the Chernobyl meltdown in 1986, he pointed out, cesium and iodine were the problem.

Of particular concern: cesium-137 in the pool, at levels Alvarez estimates at 20 million to 50 million curies.

It was established that strontium-90 and cesium-137, important in fallout on land, enter the marine cycles only in minute amounts.

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