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Title: New process of preparation, structure, and physicochemical investigations of the new titanyl phosphate Ti{sub 2}O(H{sub 2}O)(PO{sub 4}){sub 2}

Journal Article · · Journal of Solid State Chemistry
 [1]; ; ;  [2];  [3]
  1. LCMS, UFR Sciences des Materiaux Solides, Faculte des Sciences Ben M'Sik, Casablanca (Morocco)
  2. Institut de chimie de la matiere condensee de Bordeaux (ICMCB-CNRS UPR 9048), Universite de Bordeaux 1, 87 Av. Dr. Schweitzer, 33608 Pessac (France)
  3. Laboratoire Leon Brillouin, Saclay (France)

New titanyl phosphate Ti{sub 2}O(H{sub 2}O)(PO{sub 4}){sub 2} has been prepared and characterized by X-ray and neutron diffraction, nuclear magnetic resonance, infrared and Raman spectroscopies and thermogravimetric analysis. The crystal structure has been solved from neutron powder diffraction data at 300 K by Rietveld method in P2{sub 1} space group. The refinement led to satisfactory profile factors (R{sub p}=2.7%, R{sub wp}=3.2%) and crystal structure model indicators (R{sub B}=5.8%, R{sub F}=3.2%). The cell is monoclinic with a=7.3735 A, b=7.0405 A, c=7.6609 A and {beta}=121.48{sup o}, Z=4. The structure can be described as a three-dimensional framework built up by chains of [TiO{sub 5}(OH{sub 2})] octahedra with alternative short bonds [Ti{sub (1)}-O{sub (12)}; Ti{sub (2)}-O{sub (12)}, 1.88-1.84 A] and long ones [Ti{sub (1)}-O{sub W}; Ti{sub (2)}-O{sub W}, 2.25-2.23 A] along c-axis and connected via [PO{sub 4}] tetrahedra. Oxygen atom denoted O{sub (12)} is only linked to two titanium atoms and Oxygen atom denoted O{sub W} is linked to two titanium atoms and two hydrogen atoms. O{sub (12)} and O{sub W} are not linked to P atoms and justify the titanyl phosphate formulation Ti{sub 2}O(H{sub 2}O)(PO{sub 4}){sub 2}. The infrared and Raman spectra presents peaks due to vibrations of Ti-O, P-O and O-H bonds. The {sup 31}P MAS NMR spectrum reveals two {sup 31}P resonance lines, in agreement with the structure which showed two crystallographic sites for phosphorus. The thermogravimetric analysis show that Ti{sub 2}O(H{sub 2}O)(PO{sub 4}){sub 2} is thermally stable until 400 deg. C. Above this temperature, it losses water and decomposes to Ti{sub 5}O{sub 4}(PO{sub 4}){sub 4} and TiP{sub 2}O{sub 7}. - Graphical abstract: The structure of TiHP can be described as a TiOPO{sub 4} framework constituted by chains of tilted corner-sharing [TiO{sub 6}] octahedra and cross linked by [PO{sub 4}] tetrahedra with empty cavities in the framework.

OSTI ID:
21049502
Journal Information:
Journal of Solid State Chemistry, Vol. 180, Issue 10; Other Information: DOI: 10.1016/j.jssc.2007.07.028; PII: S0022-4596(07)00305-2; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
Country of Publication:
United States
Language:
English