a substance, formed by decay of radon, that gives rise to radium B.
noun, Chemistry. 1. an isotope of lead, formed by decay of radium A, that gives rise to radium C, which is an isotope of bismuth, from which radium D, radium E, and radium F, or polonium 210, are derived.
noun, Chemistry. 1. (formerly) .
noun, Chemistry. 1. an isotope of polonium: polonium 210.
noun, Chemistry. 1. a white, crystalline, water-insoluble, poisonous, radioactive solid, RaSO 4 , used chiefly in radiotherapy.