Two Modifications of Hg5Re2O10

Abstract

Abstract The previously reported mercury perrhenate Hg5Re2O10, prepared hydrothermally, has now been obtained by reaction of HgO with the mercury(II) metaperrhenate Hg(ReO4)2 in sealed silica tubes. A second modification of this compound can be obtained by reaction of elemental mercury with Hg(ReO 4)2 also in sealed silica tubes. Its crystal structure has been determined from single-crystal X-ray data: P21/c, a - 861.5(1), b = 1200.9(2), c = 1203.9(2) pm, β = 97.15(1)°, Z = 4, R = 0.024 for 1733 structure factors and 105 variables. Both modifications may be represented by the formula Hg2+-2Hg2O - 2ReO4-, indicating that mercury occurs in oxidation states I and II. In both modifications the mercury and some oxygen atoms form two-dimensionally infinte, puckered, cationic nets of the composition (Hg2+-2Hg2O)n , which are separated by the ReO4- tetrahedra. In the modification reported earlier the mercury oxygen nets consist of condensed 16-membered rings, while the nets of the present modification contain 10- and 22-membered rings.