Hydrothermal synthesis and structure determination of Na2Zn{O3P-CH2-PO3}.H2O(MIL-58):: a new zincomethylenediphosphonate exhibiting a hybrid zeotype

Na2Zn[O3P-CH2-PO3).H2O (labelled MIL-58) was hydrothermally synthesized at 443 K in the quaternary system ZnCl2 : H2O3P-CH2-PO3H2 : NaOH : H2O. Its orthorhombic structure was solved from single crystals X-ray diffraction data in the non-centrosymmetric P2(1)2(1)2(1) (No. 19) space group with lattice parameters a = 8.3215(7), b = 9.3276(8), c = 9.6958(8) Angstrom, V = 752.6(l) Angstrom(3), Z = 4, R-1 (F-o) = 0.0582, wR(2)(F-o(2)) = 0.1256 for 1945 reflections I greater than or equal to 2sigma(I). Its three-dimensional structure is built up from corner-shared trimers containing one ZnO4 tetrahedron chelated by one methylenediphosphonate unit. The connections between the trimers generate eight-membered channels where the Na+ cations and the water molecules are located. (C) 2002 Editions scientitiques et medicales Elsevier SAS. All rights reserved.