Hybrid open-frameworks.: Hydrothermal synthesis and structure determination of MIL-40 or VIVO(H2O){HO3P-CH2-(C6H4)-CH2-PO3H}:: a lamellar vanadodiphosphonate prepared with p-xylendiphosphonic acid

(VO)-O-IV(H2O){HO3P-CH2-(C6H4)-CH2-PO3H} labelled MIL- 40 is a hybrid organic-inorganic compound whose bidimensional structure is built up from (V-IV = O)(2+) vanadyl groups and p-xylendiphosphonate units. MIL-40 was hydrothermally prepared at 443 K and its structure solved from single crystal X-ray diffraction data. It is triclinic (space group <P(1)over bar >, n degrees 2) with lattice parameters a = 7.2558(8)Angstrom, b = 7.5739(8)Angstrom, c = 11.493(1)Angstrom, alpha = 93.230(2) degrees, beta = 103.018(2)degrees, gamma = 96.871(2)degrees, V = 608.7(1)Angstrom, Z = 2, R-1(F-0) = 0.0911, wR(2)(F-0(2)) = 0.1896 for 2843 unique reflections with I greater than or equal to 2 sigma (I). Its thermal decomposition is investigated. (C) 2000 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.