- a rare, highly reactive, soft, metallic element of the alkali metal group, used chiefly in photoelectric cells. Symbol: Cs; atomic weight: 132.905; atomic number: 55; specific gravity: 1.9 at 20°C; melts at 28.5°C.
Origin of cesium
Examples from the Web for cesium
Even at the Chernobyl meltdown in 1986, he pointed out, cesium and iodine were the problem.The Toxic Fuel Inside Japan's Nuclear Plant
March 15, 2011
- the usual US spelling of caesium
Word Origin and History for cesium
also caesium, rare alkaline metal, 1861, coined by Bunsen and Kirchhoff in 1860 in Modern Latin (caesium), from Latin caesius "blue-gray" (especially of eyes), in reference to the two prominent blue lines in its spectrum, by which it was first identified.
- A soft ductile metal, liquid at room temperature, the most electropositive and alkaline of the elements, used in photoelectric cells. Atomic number 55.
- 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.