RB
Rubidium (Rb) is a chemical element with atomic number 37. It is a soft, silvery-white alkali metal in group 1. Discovered in 1861 by Bunsen and Kirchhoff using flame spectroscopy, it was named for the red lines in its spectrum (rubidus meaning deep red).
Rubidium is highly reactive, reacting with water and air. It occurs only in compounds in nature. Its
Natural rubidium is relatively abundant in the crust but far less common than potassium. It occurs in
Two natural isotopes are 85Rb and 87Rb, the latter being radioactive with a half-life of about 4.9×10^10
Applications include rubidium atomic clocks and frequency standards used in timekeeping and navigation, as well as
Because of its reactivity, rubidium is handled under inert conditions or stored in mineral oil.