Wikipedia
Bismuth subcarbonate
Bismuth subcarbonate (BiO)CO, sometimes written BiO(CO) is a chemical compound of bismuth containing both oxide and carbonate anions. Bismuth is in the +3 oxidation state. Bismuth subcarbonate occurs naturally as the mineral bismutite. Its structure consists of Bi-O layers and CO layers and is related to kettnerite, CaBi(CO)OF. It is light sensitive.