Cesium
Description
An element in the alkali metal group. Cesium has an abundance of 1 ppm in the earth's crust. It occurs in the minerals pollucite and lepidolite. Cesium was discovered in 1860 by Robert Bunsen and Gustav Kirchhoff. It is a soft, silvery white metal that tarnishes on contact with air and can ignite spontaneously in moist air. Cesium is used as a catalyst for polymers and as a radioactive emitter in atomic clocks. It is also used in photoelectric sensors for security devices and cameras.
Synonyms and Related Terms
Cs; caesium (IUPAC); cesium (US,. Ned., Sven.); césium (Fr.); Cäsium (Deut.); cesio (It., Esp.); Césio (Port.)
Other Properties
Flame color is blue to purple. Violently decomposes in water with the evolution of hydrogen. Soluble in liquid ammonia.
| Composition | Cs (atomic no. 55) |
|---|---|
| CAS | 7440-46-2 |
| Mohs Hardness | 0.2 |
| Melting Point | 28.5 |
| Density | 1.873 |
| Molecular Weight | atomic wt. =132.9054 |
| Boiling Point | 705 |
Hazards and Safety
Metallic cesium can ignite spontaneously in moist air. Dangerous fire and explosion risk. Reacts violently with oxidizing materials. Burns skin.
Fisher Scientific: MSDS
Additional Information
Web Elements: Website
Sources Checked for Data in Record
- G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 180
- Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993
- Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
- Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997
- The Merck Index, Martha Windholz (ed.), Merck Research Labs, Rahway NJ, 10th edition, 1983 Comment: entry 2051
- The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998