Carbonic anhydride

Carbonic anhydride may refer to:
 * Carbon dioxide, the acidic oxide of carbonic acid
 * Dicarbonic acid, the of carbonic acid using two molecules
 * 1,3-Dioxetanedione, the dianhydride of carbonic acid using two molecules
 * 1,3,5-Trioxanetrione, the dianhydride of carbonic acid using three molecules