The electronic structure of complexes [Ru(XY)L₅]^q (L = NH₃, CI^-, CN^-; XY = NO, CO, N₂) was represented as a combination of valence schemes based on ab initio and semiempirical quantum-chemical calculations. It was found that schemes corresponding to a covalent π bond between Ru(III) and NO contribute most in the case of the complexes containing a {RuNO}³⁺ group, which makes possible the nitroso ligands in these compounds to be considered as uncharged NO molecules. The necessity of inclusion of electron correlation in the description of π interactions between the metal and ligands was shown.