Monetite (CaHPO4) Synthesis in Ethanol at Room Temperature
A straightforward process was developed to synthesize monetite (CaHPO4, dicalcium phosphate anhydrous) powders at room temperature (21°±1°C) in ethanol solutions. The process reported here constitutes an alternative to well-publicized monetite synthesis procedures based on the dehydration of brushite (CaHPO4·2H2O, dicalcium phosphate dihydrate) powders either in acidic, hot (70°–95°C) aqueous solutions or in drying ovens (200°–225°C). Submicrometer monetite powders were synthesized in ethanol (ethyl alcohol) solutions containing small aliquots of concentrated H3PO4 (orthophosphoric acid, 85%). Precipitated CaCO3 (calcium carbonate, calcite form) powders with submicrometer particles were simply stirred in the above solutions in glass bottles for 3 h. The starting Ca/P molar ratio in the synthesis bottles was 0.50. Monetite powders obtained with a stacked-nanosheets particle texture did not contain any unreacted CaCO3. Monetite powders were also found to have the ability to completely transform into apatitic (apatite-like) calcium phosphate powders when soaked in calcium-containing saline solutions (i.e., 142 mM Na+, 5 mM K+, and 50 mM Ca2+ in water) for 6 days at 37°C.
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Document Type: Research Article
Affiliations: Department of Biomedical Engineering, Yeditepe University, Istanbul 34755, Turkey
Publication date: 2009-12-01