Hexafluorosilicates of cobalt(II) complexes with dimethylsulfoxide and dimethylformamide

New double complexes [Co(DMSO)6][SiF6] ⋅ 2H2O (I) and [Co(DMF)3(H2O)3][SiF6] ⋅ DMF (II) have been synthesized and studied by IR spectroscopy and X-ray diffraction. Crystals of complex I belong to the tetragonal symmetry system, space group R3, Z = 3, a = 11.8232(3) A, c = 18.4699(5) A, V = 2235.97(10) A3, ρcalc = 1.573 g/cm3. Crystals of complex II are triclinic, space group P1, Z = 2, a = 8.6264(4) A, b = 10.1419(4) A, c = 13.9657(6) A, α = 100.847(2)°, β = 98.549(2)°, γ = 93.479(2)°, V = 1181.71(9) A3, ρcalc = 1.539 g/cm3.