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n. A soft silvery-white metallic element of the alkali group that ignites spontaneously in air and reacts violently with water, used in photocells and in the manufacture of vacuum tubes. 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 Table at element.

n. A metallic chemical element (symbol Rb) with an atomic number of 37.

n. 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.

n. Chemical symbol, Rb; atomic weight, 85.25. A metal belonging to the group of elements which includes lithium, sodium, potassium, and cæsium: so named from the reddish tint of its salts.

n. a soft silvery metallic element of the alkali metal group; burns in air and reacts violently in water; occurs in carnallite and lepidolite and pollucite

"This suggestion has been of great service in spectrum analysis, and as applied by Bunsen, Kirchoff, and others, has led to the discovery of several new elements, such as rubidium and thallium, as well as increasing our knowledge of the heavenly bodies."

metallic element    metal   

rubidic   

cesium    perchlorate    magnesium    lithium    periodate