Aluminium decavanadate 25-hydrate

Al2V10O28.25H2O, Mr = 1461.46, orthorhombic, Cmma, a = 21.618(2), b = 18.414(2), c = 10.533(1) A, V = 4193(1) A3, Z=4, Dm = 2.35, Dx = 2.32 Mg m-3, λ(Mo Kα) = 0.71069 A, μ = 2.19 mm-1, F(000) = 2920, T = 298(2) K, R = 3.31%, wR = 3.49% for 1474 independent observed reflections [I > 5σ(I)]. The unit cell contains four (V10O28)6- anions located on sites of point symmetry 2/m, four [Al(OH2)6]3+ cations on 2/m sites, four [Al(OH2)6]3+ cations on 222 sites and 52 lattice water molecules, four of which show occupational disorder. The compound presents a packing characterized by successive layers parallel to (100); ionic forces and H bonds between the layers and within them stabilize the structure. (orig.)