SYNTHESIS AND CRYSTAL-STRUCTURE OF [NA(12 -CROWN-4)2]2[HG(SE4)2] CENTER-DOT 1.5 DMF

The title compound has been prepared by the reaction of Na2Se4 with me rcury acetate in DMF solution in the presence of 15-crown-5, forming d ark red crystal needles. [Na(12-crown-4)2]2[Hg(Se4(2] . 1.5 DMF crysta llizes in the space group C2/c with eight formula units per unit cell. The structure was determined with 3 824 observed unique reflections, R = 0.085. Lattice dimensions at -70-degrees-C: a = 2884(2), b = 1 407 .7(7), c = 2 843(2) pm, beta = 93.93(5)degrees. The structure consists of [Na(12-crown-4)2]+ ions with a sandwichlike coordination of the cr own ether molecules, and of [Hg(Se4)2]2-ions, in which the mercury ato m is coordinated by two tetraselenido ions in a chelating fashion. The [Hg(Se4)2]2- ions are arranged to infinite chains via Se...Se contact s.