rubidium

ru•bid•i•um n. [Chem.]

Chemistrya silver-white, metallic, active element resembling potassium, used in photoelectric cells and radio vacuum tubes. Symbol: Rb;
at. wt.: 85.47;
at. no.: 37;
sp. gr.: 1.53 at 20°C.

Neo-Latin, equivalent. to Latin rūbid(us) red (in allusion to the two red lines in its spectrum) + -ium -ium
1860–65

ru•bid′ic, adj.

Collins Concise English Dictionary © HarperCollins Publishers::

rubidium /ruːˈbɪdɪəm/ n

a soft highly reactive radioactive element of the alkali metal group; the 16th most abundant element in the earth's crust (310 parts per million), occurring principally in pollucite, carnallite, and lepidolite. It is used in electronic valves, photocells, and special glass. Symbol: Rb; atomic no: 37; atomic wt: 85.4678; half-life of ⁸⁷Rb: 5 × 10¹¹ years; valency: 1, 2, 3, or 4; relative density: 1.532 (solid), 1.475 (liquid); melting pt: 39.48°C; boiling pt: 688°C

Etymology: 19th Century: from New Latin, from Latin rubidus dark red, with reference to the two red lines in its spectrumruˈbidic adj

'rubidium' also found in these entries (note: many are not synonyms or translations):

Forum discussions with the word(s) "rubidium" in the title:

No titles with the word(s) "rubidium".

Go to Preferences page and choose from different actions for taps or mouse clicks.