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Jingwei Xu Ian S. Butler Denis F. R. Gilson 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》1999,55(14):2801
The FT-Raman spectra and the pressure dependence of the infrared spectra of the hydrated and anhydrous forms of dicalcium phosphate, CaHPO4 · 2H2O and CaHPO4, have been studied. The hydrated salt exhibits a phase transition at 21 kbar (1.0 kbar=0.1 Gpa) but no high pressure transition was observed for anhydrous dicalcium phosphate. The O–H stretching frequencies of the water molecules in CaHPO4·2H2O all showed negative pressure dependences and correlate with the OO distances. The PO–H stretch increased with increasing pressure, indicating a strong hydrogen bond. The frequencies associated with the phosphate ion showed a normal pressure dependence. 相似文献
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G. R. Sivakumar E. K. Girija S. Narayana Kalkura C. Subramanian 《Crystal Research and Technology》1998,33(2):197-205
Spherulitic monetite (CaHPO4) and brushite (CaHPO4 · H2O) of different morphologies which have close resemblance to those found in pathological joints, stones and dental calculi were crystallized in silica gel under acidic conditions. These crystals were characterized by x-ray powder diffraction, fourier transform infra-red, and thermogravimetric analyses. The molar ratios (Ca/P) were calculated from ICP analysis and found to be in agreement with the theoretical stoichiometric molar ratio. The microstructure of the spherulitic monetite crystals have been studied using scanning electron microscopy. 相似文献
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