Cesium (Cs)

Precious Metals | Atomic Number: 55

Basic Properties

Cs
55
132.905 g/mol
Element Category Precious Metals
Atomic Number 55
Atomic Weight 132.905 g/mol
Crystal Structure Body-centered cubic (BCC)

Description

Cesium is the most electropositive element and has the lowest ionization energy of all elements.
Density 1.93 g/cm³
Tensile Strength 1.2 MPa
Hardness 0.2 Mohs
Melting Point 28.4°C
Boiling Point 671°C
Thermal Conductivity 35.9 W/(m·K)
Electrical Conductivity 4.89 × 10^6 S/m
Corrosion Resistance Poor - reacts violently with water and air

Applications

Atomic clocks, photoelectric cells, catalysts, drilling fluids, medical applications

Production Methods

Reduction of cesium compounds with calcium or magnesium

History

Discovered by Robert Bunsen and Gustav Kirchhoff in 1860 via spectroscopy.