MOLECULAR MECHANICS SIMULATIONS IN STRUCTURE-ANALYSIS OF INTERCALATE VOPO4.2CH(3)CH(2)OH

Molecular mechanics simulations using Cerius(2) combined with X-ray di ffraction and supported with vibrational spectroscopy have been used t o investigate the layered structure of vanadyl phosphate VOPO4 interca lated with ethanole. This intercalated structure exhibits certain degr ee of disorder, which affects the diffraction diagram and obstructs th e conventional structure analysis based on diffraction methods only. P resent structure analysis is focused to the crystal packing in the int erlayer space and layer stacking in the intercalate. The bilayer arran gement of ethanole molecules in the interlayer has been found, giving the basal spacing d = 13.21 Angstrom, experimental d-value obtained fr om X-ray diffraction is 13.17 Angstrom. One half from the total number of CH3CH2OH molecules is anchored with their oxygens to VOPO4 layers to complete vanadium octahedra and their orientation is not very stric tly defined. The second half of ethanoles is linked with hydrogen brid ges to the anchored ethanoles and sometimes also to the layer oxygens. Positions and orientations of these unachored ethanoles with respect to VOPO4 layers exhibit certain degree of disorder, resulting in the d isorder in layer stacking. Molecular mechanics simulations revealed th e character of this displacement disorder in layer stacking and enable d to determine the components of the displacement vector.