Calcified Tissue International

, Volume 35, Issue 1, pp 783–790

An intermediate state in hydrolysis of amorphous calcium phosphate

  • M. S. Tung
  • W. E. Brown
Laboratory Investigations

DOI: 10.1007/BF02405124

Cite this article as:
Tung, M.S. & Brown, W.E. Calcif Tissue Int (1983) 35: 783. doi:10.1007/BF02405124


The hydrolysis of previously prepared amorphous calcium phosphate (ACP) was studied in a solution “saturated” with ACP; this eliminated the initial consumption of acid due to ACP dissolution. The procedure established that conversion of a high-concentration ACP slurry to an apatite involves two processes: the first process consumes acid and indicates the formation of a more acidic calcium phosphate intermediary with the solubility of octacalcium phosphate (OCP); the second process consumes base and indicates the conversion of the intermediary to apatite and, possibly, direct conversion of ACP to apatite. The thermodynamic analysis of the solution composition data suggests that ACP converts into a nonstoichiometric apatite when the OCP-like intermediary is formed, and a stoichiometric apatite is formed when no OCP-like intermediary is involved.

Key Words

Amorphous calcium phosphate Apatite Calcification Hydrolysis Octacalcium phosphate 

Copyright information

© Springer-Verlag New York Inc. 1983

Authors and Affiliations

  • M. S. Tung
    • 1
  • W. E. Brown
    • 1
  1. 1.American Dental Association Health FoundationResearch Unit, National Bureau of StandardsWashington, DCUSA

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