from
The Collaborative International Dictionary of English v.0.48
Rubidium \Ru*bid"i*um\, n. [NL., fr. L. rubidus red, fr. rubere
to be red. So called from two dark red spectroscopic lines by
means of which it was discovered in the lepidolite from
Rozena, Moravia. See {Rubicund}.] (Chem.)
A rare metallic element of the alkali metal series, atomic
number 37. It occurs quite widely, but in small quantities,
and always combined. It is isolated as a soft yellowish white
metal, analogous to potassium in most of its properties.
Symbol Rb. Atomic weight, 85.48.
[1913 Webster]
from
The Elements (07Nov00)
rubidium
Symbol: Rb
Atomic number: 37
Atomic weight: 85.47
Soft silvery metallic element, belongs to group 1 of the periodic table.
Rb-97, the naturally occurring isotope, is radioactive. It is highly
reactive, with properties similar to other elements in group 1, like
igniting spontaneously in air. Discovered spectroscopically in 1861 by
W.
Bunsen and G.R. Kirchoff.