Skip links

Rubidium (Rb): Fun Facts and Information About the Element


What is the symbol? Rb
What is the atomic number? 37
What is the atomic weight? 85.4678
What is the melting point in Celsius? 39
What is the boiling point in Celsius? 688
What is the density (g/cm3)? 1.63
What year was it discovered? 1861
Who discovered the element? “Robert Bunsen and Gustav Kirchoff”
What group is the element in? 1
What is the electron configuration? [Kr] 5s1
What is the ionization energy? 4.1771
What element category is it in? Alkali metals

Where is Rubidium Found?

The element is much more abundant than was thought several years ago. It is now considered to be the 16th most abundant element in the earth’s crust. Rubidium occurs in pollucite, leucite, and zinnwaldite, which contains traces up to 1%, in the form of the oxide. It is found in lepidolite to the extent of about 1.5%, and is recovered commercially from this source.

What is Rubidium Used For?

Because rubidium can be easily ionized, it has been considered for use in “ion engines” for space vehicles. It is also proposed for use as a working fluid for vapor turbines and for use in a thermoelectric generator. Rubidium is used as a getter in vacuum tubes and as a photocell component. It has been used in making special glasses.