October 31 - November 3, 2004
Element of the Day
Monday, November 1
Latin:
caesius: sky blue. One of the world's richest sources of cesium is located at
Bernic Lake, Manitoba. The deposits are estimated to contain 300,000 tons of
pollucite, averaging 20% cesium. Cesium,
gallium, and mercury are the only three metals that are liquid at room
temperature. Cesium reacts explosively with cold water, and reacts with ice at
temperatures above –116 oC. Cesium hydroxide, the strongest base
known, attacks glass.
Discovered by: Cesium was discovered spectroscopically in 1860 by Bunsen and Kirchhoff in mineral water from Durkheim.
Uses: Because it has great affinity for oxygen, the metal is used as a "getter" in electron tubes. It is also used in photoelectric cells, as well as a catalyst in the hydrogenation of certain organic compounds.
The metal has recently found application in ion propulsion systems. Cesium is used in atomic clocks, which are accurate to 5 s in 300 years. Its chief compounds are the chloride and the nitrate.