Radium Carbonate, RaCO₃

Radium Carbonate, RaCO₃, may be obtained by fusion of the sulphate with an alkali carbonate, or by boiling with a solution of the latter. It may also be precipitated from solutions of soluble radium salts by ammonium carbonate. It is insoluble in water, but dissolves readily in hydrochloric acid.

Radium might be concentrated in mixtures of the alkaline earths by fractional precipitation of the carbonates, radium being precipitated last.