CRYSTAL-GROWTH AND STRUCTURE OF COSO4-CENTER-DOT-PYRAZINE-CENTER-DOT-6H2O(I) AND (COSO4)2-CENTER-DOT-PYRAZINE-CENTER-DOT-12H2O(II)

Single crystals of mu-pyrazino-bis[pentaquacobalt(II)]-sulfate-dihydrate CoSO4(pz).6H2O and Tetraqua-mu-pyrazino-cobalt(II)sulfate-dihydrate (CoSO4)2(pz) . 12H2O were grown by using gel methods and investigated by X-ray analysis. CoSO4(pz) . 6H2O (I) shows monoclinic symmetry, space group C2/c; a = 1006.4(4) pm, b = 1026.9(4) pm, c = 1261.5(2) pm; beta = 104.01(4)-degrees; Z = 4. (CoSO4)2(pz) . 12H2O (II) shows orthorhombic symmetry, space group Pbam; a = 1262.3(4) pm, b = 1231.3(4) pm, c = 684.1(2) pm; Z = 2. CoSO4 and Pyrazine crystalline in a polymeric (I) as well as in a dimeric (II) compound. In the polymeric compound the molecules are bonded by pyrazine to form alternating linear chains. The dimer is a dinuclear complex with a bridging pyrazine molecule.