A soft, silvery, ductile, metallic element
produced as a by-product of zinc refining and
by reduction of cesium chloride. It is found mainly as the mineral pollucite.
Cesium is one of the alkali metals,
found in Group I of the periodic table.
It is the most electropositive and alkaline of elements, turns to a liquid
at only 28.5°C, and burns spontaneously in moist air. It is used in
photoelectric cells, as a catalyst promoter, and to make special glass.
The radioisotope cesium-137 can be
employed in radiotherapy, but is now rarely used. The cesium (atomic) clock
provides the standard measure of time: the electron resonance frequency
of the cesium atom is exactly 9,192,631,770 cycles per second. Cesium has
also been used in ion propulsion.
Justin Urgitis, Wikipedia
Cesium was discovered by Robert Bunsen and
Gustav Kirchhoff in Heidelberg, Germany,
in 1860. Its name comes from the Latin caesius meaning "sky blue."
|relative atomic mass
|first ionization energy