M. Harcharras, A. Ennaciri, H. Assaaoudi
Apr 1, 2003
Citations
0
Influential Citations
26
Citations
Journal
Journal of Solid State Chemistry
Abstract
Abstract A tetrasodium dimagnesium dihydrogen diphosphate octahydrate Na 4 Mg 2 (H 2 P 2 O 7 ) 4 ·8H 2 O was synthesized. It crystallizes in the monoclinic system, space group P 2 1 / m (no. 11), Z =4, and its unit-cell parameters are: a =8.0445(3) A, b =11.5244(5) A, c =9.0825(4) A, β =113.1401(2)°, V =774.28(6) A 3 . The structure was determined by single-crystal X-ray diffractometry and refined to a R index of 0.0294 (w R =0.0727) for 1878 independent reflections with I >2 σ ( I ). The framework is made by the alternance of layers of MgO 6 /NaO 6 octahedra and double tetrahedra PO 4 along b -axis. Such layers are characterized by the presence of strong hydrogen bonds. (H 2 P 2 O 7 ) 2− anions exhibit bent eclipsed conformation. Besides, the crystal was analyzed by FT–IR and micro-Raman vibrational spectroscopy. No coincidences of the majority of the Raman and infrared spectra bands of Na 4 Mg 2 (H 2 P 2 O 7 ) 4 ·8H 2 O confirms a centrosymmetric structure of this material. The vibrational spectra confirm the bent POP configuration in this compound.