Thermal changes in synthetic deuterioxyapatite
Deuterioxyapatite (Ca<SUB>10</SUB>(PO<SUB>4</SUB>)<SUB>6</SUB>(OD)<SUB>2</SUB>, DAp) was prepared from CaO, P<SUB>2</SUB>O<SUB>5</SUB>, and D<SUB>2</SUB>O in H<SUB>2</SUB>O and CO<SUB>2</SUB> free air at 298K. The obtained DAp was identified as apatite single phase by a powder XRD technique. The deuterioxyl group was found by IR and MAS-NMR techniques, but hydroxyl group was not. Further, MAS-NMR measurement suggested the DAp had no tightly-bonded OD group. The deuterioxyl group was not substituted with hydroxyl group at 298K by stirring in distilled water for 7 days. From TG-MS measurement, dried DAp powder released deuterium in two rapid steps and in a slow step up to 873K. High-temperature XRD measurement showed large thermal expansion for DAp due to lattice defect led by heating. High-temperature IR spectra showed release of deuterioxyl group without substitution by hydroxyl group above 333K. Deuterioxyl group in DAp was easily released by heating, and DAp changed into oxyapatite.
- Mineralogical journal
Mineralogical journal 18(3), 79-86, 1996-07-01
Japan Association of Mineralogical Sciences