Isolation and Molecular Structure of Hexacyanoruthenate(III)

The [Ru(CN)6]3- ion is synthesized in aqueous solution and isolated as [Ph4As]3[Ru(CN)6]·2H2O (1). Compound 1 crystallizes as orange needles in the monoclinic space group P21/n with cell parameters a = 11.346(2) (angstrom), b = 23.107(5) (angstrom), c = 25.015(5) (angstrom), (beta)= 99.55(3) °, V = 6467.1(22) (angstrom)3, Z = 4. The octahedral anion has Ru-C bond lengths in the range 2.023(6)-2.066(6) (angstrom). DFT calculations reproduce experimental geometries for [M(CN)6]3- (M = Fe, Ru) equally well and yield significantly higher spin densities on the cyanide ligands in [M(CN)6]3- (M = Ru, Os) than in [Fe(CN)6]3-.