M(REO4)(2)CENTER-DOT-4H(2)O (M=CO, ZN) - PREPARATION AND CRYSTAL-STRUCTURE DETERMINATION

Single crystals of cobalt perrhenate tetrahydrate and zinc perrhenate tetrahydrate were characterized by X-ray single-crystal structure anal ysis (299 K; MoK alpha radiation, 71.069 pm). Crystals of Co(ReO4)(2) . 4H(2)O and Zn(ReO4)(2) . 4H(2)O are triclinic, with space group P $$ ($) over bar 1. Co(ReO4)(2) 4H(2)O has the following parameters: a = 6 54.4(9) pm, b = 687.9(8) pm, c = 727.6(2) pm, alpha = 64.61(1)degrees, beta = 70.52(2)degrees, gamma = 71.76(1)degrees, and D-x = 3.84 g cm( -3). Zn(ReO4)(2) . 4H(2)O has the following parameters: a = 651.0(3) p m, b = 697.2(3) pm, c = 721.0(3) pm, alpha = 64.53(1)degrees, beta = 7 0.31(1)degrees, gamma = 72.10(1)degrees, and D-x = 3.85 g cm(-3). The structure consists of almost tetrahedral ReO4- units, octahedrally coo rdinated cations M(2) + (M = Co, Zn), and water molecules. Each M(2+) cation is surrounded by six oxygen atoms belonging to two different Re O4- anions and four water molecules forming a slightly distorted octah edron. The octahedra and tetrahedra are linked to each other parallel to [101]. (C) 1995 Academic Press, Inc.