New process of preparation, structure, and physicochemical investigations of the new titanyl phosphate Ti2O(H2O)(PO4)2

New titanyl phosphate Ti2O(H2O)(PO4)(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(1) space group. The refinement led to satisfactory profile factors (R-p = 2.7%, R-wp = 3.2%) and crystal structure model indicators (R-B = 5.8%, R-F = 3.2%). The cell is monoclinic with a = 7.3735 angstrom, b = 7.0405 angstrom, c = 7.6609 angstrom and beta = 121.48 degrees, Z = 4. The structure can be described Lis a three-dimensional framework built up by chains of [TiO5(OH2)] octahedra with alternative short bonds [Ti-(1)-O-(12); Ti-(2)-O-(12), 1.88-1.84 angstrom] and long ones [Ti-(1)-O-W; Ti-(2)-O-W, 2.25-2.23 angstrom] along c-axis and connected via [PO4] tetrahedra. Oxygen atom denoted O-(12) is only linked to two titanium atoms and Oxygen atom denoted O-W is linked to two titanium atoms and two hydrogen atoms. O-(12) and O-W are not linked to P atoms and justify the titanyl phosphate formulation Ti2O(H2O)(PO4)(2). The infrared and Raman spectra presents peaks due to vibrations of Ti-O, P-O and O-H bonds. The P-31 MAS NMR spectrum reveals two P-31 resonance lines, in agreement with the structure which showed two crystallographic sites for phosphorus. The thermogravimetric analysis show that Ti2O(H2O)(PO4)(2) is thermally stable until 400 degrees C. Above this temperature, it losses water and decomposes to Ti5O4(PO4)(4) and TiP2O7. (C) 2007 Elsevier Inc. All rights reserved.