Superphosphate

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An acid phosphate. Superphosphate of lime (Com. Chem.), afertilizer obtained by trating bone dust, bone black, or phosphoritewith sulphuric acid, whereby the insoluble neutral calcium phosphate,Ca3(PO4)2, is changed to the primary or acid calcium phosphateCa(H2PO4)2, which is soluble and therefore available for the soil.