VF(C4O4)(H2O)2: a new layer type of diaquavanadium(III) fluoride squarate.

Single crystals of the title compound, poly[diaqua-mu-fluoro-mu-squarato-vanadium(III)], [V(C4O4)F(H2O)2]n, have been prepared hydrothermally at 423 K. This compound is shown to have a layer-type structure. The V and F atoms are localized on the symmetry centers 2a and 2d, respectively, of the monoclinic system (space group P2(1)/n) and they form infinite chains which are bridged by the squarate group acting as a bidentate ligand in a trans position. Two water molecules complete the octahedral coordination of vanadium(III). The three-dimensionality is ensured by a strong O-H...O hydrogen bond.