rubidium

• POS: Noun
• HYPHEN: ru=bid=i=um

CIDE DICTIONARY

rubidium, 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.].

 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]

OXFORD DICTIONARY

rubidium, n. Chem. a soft silvery element occurring naturally in various minerals and as the radioactive isotope rubidium-87.

Usage

Symb.: Rb.

Etymology

L rubidus red (with ref. to its spectral lines)