Rietveld refinement and spectroscopic studies of sodium lead fluoroapatite lacunaire synthesized by hydrothermal method
- Laboratoire de L'Etat Solide (LES), Faculte des Sciences de Sfax, Route de Soukra Km 3.5, BP 802, 3018 Sfax (Tunisia)
The structure of NaPb{sub 9}(PO{sub 4}){sub 6}F(H{sub 2}O){sub 0.33}, isostructural with apatite, was determined by X-ray powder diffraction methods and the result of Rietveld refinement is P6{sub 3}/m, a = 9.76396(8) A and c = 7.27520(9) A. The final refinement led to R{sub F} = 5.4%, R{sub B} = 6.6%. In the tunnel, the water molecule (O{sub w}) and F{sup -} ions appear to be located in 2b and 4e sites, with occupancies of 0.028(6) and 0.075(8), respectively. In the M(1) and M(2) sites the occupancies of Pb and Na are 0.282(3)/0.051(3) and 0.467(5)/0.033(5), respectively. The formula assigned to the compound is [Pb{sub 3.38(4)}Na{sub 0.62(4)}](1)[Pb{sub 5.60(6)}Na{sub 0.40(6)}](2)(PO{sub =} 4){sub 6}F{sub 0.90(10)}(H{sub 2}O){sub 0.33(7)}{open_square}{sub 0.77(17)}, where {open_square} = vacancy. The assignment of the observed frequencies in the Raman and infrared spectra is discussed on the basis of a unit-cell group analysis and by comparison with fluor and chloroapatite analogs. The result of {sup 31}P and {sup 23}Na magic angle spinning-nuclear magnetic resonance (MAS-NMR) spectroscopies confirmed the structural results.
- OSTI ID:
- 21144010
- Journal Information:
- Materials Research Bulletin, Vol. 43, Issue 6; Other Information: DOI: 10.1016/j.materresbull.2007.06.055; PII: S0025-5408(07)00299-1; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ABSORPTION SPECTROSCOPY
APATITES
FLUORINE COMPOUNDS
FLUORINE IONS
HEXAGONAL LATTICES
HYDROTHERMAL SYNTHESIS
INFRARED SPECTRA
LEAD COMPOUNDS
NUCLEAR MAGNETIC RESONANCE
ORGANIC FLUORINE COMPOUNDS
PHOSPHORS
PHOSPHORUS 31
RAMAN SPECTROSCOPY
SODIUM 23
SODIUM COMPOUNDS
VACANCIES
X-RAY DIFFRACTION