Certain cycloalkane-1,1-diphosphonic acids and derivatives thereof having the ability to treat diseases associated with abnormal calcium and phosphate metabolism

A cyclic diphosphonic acid, or a pharmaceutically-acceptable salt thereof, having the structure:

• ##STR9## wherein R.sub.1 is selected from the group consisting of alkyl having from 1 to 6 carbon atoms, substituted alkyl having from 1 to 6 carbon atoms, phenyl, substituted phenyl, naphthyl, substituted naphthyl, benzyl, substituted benzyl, hydroxy, halogen, amino, substituted amino, acyl amino having from 1 to 6 carbon atoms, carboxy, carbonyl, and alkoxy;
• and said substituted R.sub.1 groups are substituted with a member selected from the group consisting of methyl, amino, C.sub.1 -C.sub.6 alkylamino, chloro, hydroxy and methoxy.