The results of ab initio quantum-chemical calculations of isolated ruthenium(II) complexes cis- [Ru(bpy)₂(bipy)(X)]⁴4q (bpy is 2,2'-bipyridyl, bipy is 4,4'-bipyridyl; X = NH₃, Cl^-, Br^-, CN^-, NO^-₂, ONO^-, MeCN, and NO⁺) are presented. Analysis of the charge distributions and the orbital structures of the complex ions points to absence of strong π-acceptor bonds Ru-bpy, Ru-bipy, and Ru-X (X = NO⁺), to delocalization of π-electron density under the action of strong donors X, to localized nature of lowest unoccupied molecular orbitals, and to special position of the nitrosyl complexes in this series.