Structural characterisation of MII guanidinium sulphate hydrates (MII = Mn, Fe, Co, Ni, Cd, VO)

The crystal structures of six M-II guanidinium double sulphates have been determined from single-crystal X-ray diffraction data collected with a CCD area detector at 293 K and were refined. These are the triclinic (space group P - 1, Z = 1) tetrahydrates [C(NH2)(3)](2)Mn-II(H2O)(4)(SO4)(2) (a = 6.368(1) Angstrom, b = 6.426(1) Angstrom, c = 9.952(2) Angstrom, alpha = 90.01(1)degrees, beta = 97.03(1)degrees, gamma = 110.07(1)degrees, V = 379.2(1) Angstrom(3)) and [C(NH2)(3)](2)Cd(H2O)(4)(SO4)(2) (a = 6.441(1) Angstrom, b = 6.459(1) Angstrom, c = 10.015(2) Angstrom, alpha = 90.18(1)degrees, beta = 97.02(1)degrees, gamma = 110.00(1)degrees, V = 386.3(1) Angstrom(3)), the monoclinic (space group P2(1)/c, Z = 2) hexahydrates [C(NH2)(3)](2)Fe-II(H2O)(6)(SO4)(2) (a = 10.011(2) Angstrom, b = 7.657(2) Angstrom, c = 12.030(2) Angstrom, beta = 96.85(3)degrees, V = 915.6(3) Angstrom(3)), [C(NH2)(3)](2)Ni(H2O)(6)(SO4)(2) (a = 10.026(1) Angstrom, b = 7.633(1) Angstrom, c = 12.025(1) Angstrom, beta = 97.09(1)degrees, V = 913.4(1) Angstrom(3)) and [C(NH2)(3)](2)Co(H2O)(6)(SO4)(2) (a = 10.079(1) Angstrom, b = 7.654(1) Angstrom, c = 12.021(2) Angstrom, beta = 97.02(1)degrees, V = 920.4(2) Angstrom(3)) as well as the triclinic (space group P - 1, Z = 4) vanadyl compound [C(NH2)(3)](2)VO(H2O)(4)(SO4)(2) (a = 7.366(1) Angstrom, b = 12.366(2) Angstrom, c = 19.302(4) Angstrom, alpha = 107.10(3)degrees, beta = 94.07(3)degrees, gamma = 90.05(3)degrees, V = 1675.8(5) Angstrom(3)). An investigation of the crystal structures shows layering of the units for all compounds. Three structure types can be distinguished. These types are compared in terms of arrangement and connection of the layers. Comparisons with structurally related compounds are discussed. (C) 2004 Elsevier SAS. All rights reserved.