ISSN:
1432-0827
Keywords:
Calcium hydroxyapatite
;
Lead hydroxyapatite
;
Cation distribution
;
Lattice parameters
;
Solid solutions
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
,
Physics
Notes:
Summary Solid solutions of calcium hydroxyapatite (CaOHA) and lead hydroxyapatite (PbOHA) of the formula Ca10−x Pbx (PO4)6 (OH)2 were prepared by coprecipitation followed by heating at 800°C in a stream of CO2-free water vapor of 1 atm. The samples were apatitic in the range 0〈x〈6 and contained lead phosphates as a second phase at higher Pb/Ca ratios. Lattice parameters and cation distribution of the apatitic samples were determined by X-ray diffraction. The lattice parameters varied linearly with x in the range considered, whereas all Pb2+ were located in the sixfold position for cations. There was a miscibility gap in the apatite series of solid solutions in the range 1〈x〈4, whereas apatites in the range 6〈x〈10 were not stable under the conditions of preparation. It is concluded that apatites in the range 4〈x〈6 represent a minimum in the free energy of solid solutions between CaOHA and PbOHA.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02409444
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