Magnesium action on the stability of fluorapatite.
Fluorapatites with various magnesium contents (Mg-FAp) were synthesized at pH 7.4 and 80 degrees C. The contraction of their c-axis dimensions observed in X-ray diffraction analysis, together with the results of chemical analyses, suggested that Mg2+ ions may substitute into the apatite crystals to a limited extent. The apatites became less well crystallized with increase in magnesium content. At any given magnesium-calcium feed-in molar ratio (Mg/Ca)f, the magnesium uptake by Mg-FAp was higher than that by the corresponding F- -free Mg-HAp. Therefore, the former became amorphous at lower (Mg/Ca)f than the latter. However, in terms of crystallographic considerations, the Mg-FAp synthesized at high (Mg/Ca)f revealed its apatitic features after pyrolysis at 1,000 degrees C, while Mg-HAp displayed the tricalcium phosphate X-ray pattern.
Okazaki
M
M
Department of Dental Technology, Osaka University, Faculty of Dentistry, Japan.
D001031:Apatites / Q000032:analysis / Q000138:chemical synthesis; D002118:Calcium / Q000032:analysis; D055598:Chemical Phenomena; D011232:Chemical Precipitation; D002627:Chemistry, Physical; D003460:Crystallization; D004355:Drug Stability; D006358:Hot Temperature; D008274:Magnesium / Q000032:analysis; D008854:Microscopy, Electron; D014961:X-Ray Diffraction
D001031:Apatites; D008274:Magnesium; C025105:fluorapatite; D002118:Calcium