Calcium Metaplumbate, CaPbO₃.4H₂O

Calcium Metaplumbate, CaPbO₃.4H₂O, is formed by heating the orthoplumbate alone or in presence of potash. By heating in air near 250° C., water is lost and a reddish-brown powder formed, probably containing a small quantity of calcium perplumbate, CaPb₂O₆.

Kassner suggested that calcium plumbate might be used to oxidise potassium ferrocyanide to ferricyanide, carbon dioxide being passed in to neutralise the potassium hydroxide formed. The residual mixture of calcium and lead carbonates could be retransformed into calcium plumbate by heating in air.