Bone Carbonate and the Ca to P Molar Ratio

Abstract

IT is customary to consider the bone salt either as hydroxy-apatite or as tribasic calcium phosphate, principally on the basis of stoichiometric and X-ray diffraction studies¹. Nonetheless, the observed molar ratio of Ca/P in the bone salt in most vertebrates is quite variable, and is usually in excess of 1.67, which is the ratio one would expect for hydroxyapatite^2–4. Few studies deal directly with this discrepancy, and its dependence on the calcium carbonate content of bone has not been clearly demonstrated.