CaH2PO42

Superphosphate Su`per*phos"phate, n. (Chem.) An acid phosphate. [1913 Webster]

{Superphosphate of lime} (Com. Chem.), a fertilizer obtained by trating bone dust, bone black, or phosphorite with sulphuric acid, whereby the insoluble neutral calcium phosphate, {Ca3(PO4)2}, is changed to the primary or acid calcium phosphate {Ca(H2PO4)2}, which is soluble and therefore available for the soil. [1913 Webster]