Rubidium is a soft, silvery-white metallic element of the alkali metal group.
Core Principles & Analysis
Robert Bunsen and Gustav Kirchhoff discovered rubidium in 1861 through its deep red spectral lines, naming it from the Latin 'rubidus' for darkest red.
The alkali metal melts at 39 C, ignites spontaneously in air, and reacts explosively with water.
Rubidium frequency standards keep time in GPS and telecom networks, and rubidium-87 atoms formed the first Bose-Einstein condensate in 1995.