Cs - Cesium
(L. caesius, sky blue) Cesium was discovered spectroscopically by Bunsen and Kirchhoffin 1860 in mineral water from Durkheim.
Cesium, an alkali metal, occurs in lepidolite, pollucte (a hydrated silicate ofaluminum and cesium), and in other sources. One of the world's richest sources of cesiumis located at Bernic Lake, Manitoba. The deposits are estimated to contain 300,000 tons ofpollucite, averaging 20% cesium.
It can be isolated by elecytrolysis of the fused cyanide and by a number of othermethods. Very pure, gas-free cesium can be prepared by thermal decomposition of cesiumazide.