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Webster 1913 Edition
Rubidium
Ru-bid′i-um
,Noun.
[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.