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) Å, b = 23.107(5) Å, c = 25.015(5) Å, β =
99.55(3)°, V = 6467.1(22) Å3, Z = 4. The octahedral anion has
Ru−C bond lengths in the range 2.023(6)−2.066(6) Å. 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-.