The dissolution of dicalcium phosphate dihydrate has been studied by following changes in the calcium, phosphate, and hydrogen ion concentrations when undersaturated solutions are inoculated with seed crystals of the salt. The rate of dissolution follows an equation of the first order with respect to concentration; this suggests a diffusion-controlled process and changes in the rate of stirring that have a considerable effect on the observed rate. Experiments have been made at 15, 25, and 37 C and the energy of activation corresponding to the dissolution process is 3.8 kcal mol-1.
Get full access to this article
View all access options for this article.
References
1.
Brown, W.E., and Lehr, J.R.: Application of Phase Rules to the Chemical Behavior of Monocalcium Phosphate Monohydrate in Soils, Soil Sci Soc Amer Proc23:7-11, 1959.
2.
Lehr, J.R., and Brown, W.E.: Calcium Phosphate Fertilizers: II. A Petrographic Study of Their Alteration in Soils, Soil Sci Soc Amer Proc22:29-32, 1958.
3.
Sobel, A.E.; Burger, M.; and Nobel, S.: Mechanisms of Nuclei Formation in Mineralizing Tissues, Clin Orthop17 :103-119, 1960.
4.
Lonsdale, K.: Epitaxy as a Growth Factor in Urinary Calculi and Gall-Stones, Nature217:56-58, 1968.
5.
Keyes, P.H., and Jordan, V.: Mechanisms of Hard Tissue Destruction, Washington, DC.AAAS, 1963, p 261.
6.
Gray, J.A.: Kinetics of the Dissolution of Human Dental Enamel in Acid, J Dent Res41:633-645, 1962.
7.
Francis, M.D. : Solubility Behavior of Dental Enamel and Other Calcium Phosphates, Ann NY Acad Sci131:694-712, 1965.
8.
Higuchi, W.I. ; Gray, J.A.; Hefferren , J.J.; and Patel, P.R.: Mechanisms of Enamel Dissolution in Acid Buffers, J Dent Res44:330-341, 1965.
9.
Marshall, R.W. , and Nancollas, G.H.: The Kinetics of Crystal Growth of Dicalcium Phosphate Dihydrate, J Phys Chem73:3838-3844, 1969.
10.
Arnold, P.W. : The Nature of Precipitated Calcium Phosphates , Trans Faraday Soc46:1061-1072, 1950 .
11.
Berry, E.E. , and Baddiel, C.D.: The Infra-Red Spectrum of Dicalcium Phosphate Dihydrate (Brushite), Spectrochim Acta23A:2089-2097, 1967.
12.
Fogg, D.N., and Wilkinson, N.T.: The Colorimetric Determination of Phosphorus, Analyst (London) 83:406-414, 1958.
13.
Bates, R.G.: Determination of pH, New York: John Wiley & Sons, Inc., 1963.
