Name :  Caesium
Symbol :  Cs
Atomic Number :  55
Atomic Weight :  132.90543
Specific Heat :  0.24 J/gK
Melting Point :  28.4°C
Vaporization :  67.740 kJ/mol
Boiling Point :  669.3°C
Electronegativity :  0.79
Density@293 K :  1.873 g/cm³
Discovered :  Gustov Kirchoff, Robert Bunsen, Germany, 1860
Description :  Very soft, light gray, ductile metal.
Uses :  Used as a \'getter\' to remove air traces in vacuum and cathode-ray tubes. Also used in producing photoelectric devices and atomic clocks. Since it ionizes readily, it is used as an ion rocket motor propellant.