We have studied the molecular orbitals of ruthenium halides, in order to study the extent of contribution of 4d, 5s and 5p orbitals in the formation of molecular orbitals. The 3D modeling and geometry optimization of the ruthenium halides have been done by CAChe software using molecular mechanics with EHT option. Eigenvector analysis shows that 4dx2- y2 and 4dxy orbitals of ruthenium play a major role in bonding between ruthenium and halogens, 5s orbital is next and 5p orbitals have a negligible role. There is a difference in energy levels of s and p orbitals of chloride and iodide are 0.1691 and 0.7472 respectively. The overlap population analysis shows that the nonbonding orbitals are present in 6th and 7th molecular orbitals in both. No molecular orbital is formed by only two atomic orbitals. All molecular orbitals have contribution from many atomic orbitals; the difference is only in extent of involvement.
