Hydrothermal synthesis and structural characterization of (NH{sub 4})GaPO{sub 4}F, KTP-type and (NH{sub 4}){sub 2}Ga{sub 2}(PO{sub 4}) (HPO{sub 4})F{sub 3}, pseudo-KTP-type materials
Two new fluorinated gallium phosphates have been hydrothermally synthesized in the system GaOOH/H{sub 2}O/H{sub 3}PO{sub 4}/HF/guanidine or NH{sub 4}F (180 C, autogenous pressure, 4 days). The structures of both compounds have been characterized by single-crystal X-ray diffraction. The (NH{sub 4})GaPO{sub 4}F phase is isostructural with the KTiOPO{sub 4} (KTP) structural type. The structure of the second phase (NH{sub 4}){sub 2}Ga{sub 2}(PO{sub 4})(HPO{sub 4})F{sub 3}, named pseudo-KTP or p-KTP, is closely related to that of KTP. In the latter, the existence of terminal P-OH and Ga-F bond along the b axis prevents the full connection by corner-sharing of the PO{sub 4} and Ga(O,F){sub 6} units as it occurs in KTP structure. It results in a more distorted framework in which the occluded ammonium cations interact mainly with the P-OH and Ga-F terminal bonds. The structure of p-KTP was examined by {sup 19}F and {sup 31}P solid-state nuclear magnetic resonance spectroscopy using high-speed MAS experiments (30 kHz). {sup 19}F NMR indicates a full occupancy by fluorine for the atomic sites bridging the gallium atoms. Crystal data is given for (NH{sub 4})GaPO{sub 4}F.
- Research Organization:
- Univ. de Versailles-St.Quentin en Yvelines (FR)
- OSTI ID:
- 20080267
- Journal Information:
- Chemistry of Materials, Vol. 12, Issue 5; Other Information: PBD: May 2000; ISSN 0897-4756
- Country of Publication:
- United States
- Language:
- English
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