rubidium
[ roo-bid-ee-uh m ]
/ ruˈbɪd i əm /
noun Chemistry.
a silver-white, metallic, active element resembling potassium, used in photoelectric cells and radio vacuum tubes. Symbol: Rb; atomic weight: 85.47; atomic number: 37; specific gravity: 1.53 at 20°C.
Origin of rubidium
1860–65; < New Latin, equivalent to Latin
rūbid(us) red (in allusion to the two red lines in its spectrum) +
-ium
-ium
OTHER WORDS FROM rubidium
ru·bid·ic, adjectiveWords nearby rubidium
Example sentences from the Web for rubidium
British Dictionary definitions for rubidium
rubidium
/ (ruːˈbɪdɪəm) /
noun
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 87 Rb: 5 × 10 11 years; valency: 1, 2, 3, or 4; relative density: 1.532 (solid), 1.475 (liquid); melting pt: 39.48°C; boiling pt: 688°C
Derived forms of rubidium
rubidic, adjectiveWord Origin for rubidium
C19: from New Latin, from Latin
rubidus dark red, with reference to the two red lines in its spectrum
Medical definitions for rubidium
rubidium
[ rōō-bĭd′ē-əm ]
n. Symbol Rb
A soft metallic element of the alkali group. Atomic number 37.
Scientific definitions for rubidium
rubidium
[ rōō-bĭd′ē-əm ]
Rb
A soft, silvery-white metallic element of the alkali group. It ignites spontaneously in air and reacts violently with water. Rubidium is used in photoelectric cells, in making vacuum tubes, and in radiometric dating. Atomic number 37; atomic weight 85.47; melting point 38.89°C; boiling point 688°C; specific gravity (solid) 1.532; valence 1, 2, 3, 4. See Periodic Table.