Some quantum chemical parameters were calculated by using Hartree-Fock (HF) approximation, Density Functional Theory (DFT/B3LYP) and Moller Plesset perturbation theory (MP3) methods at LANL2DZ, LANL2MB and SOD levels in gas phase and water for dichromate (Cr2O72-), chromate (CrO42-), tungstate (WO42-), molybdate (MoO42-), nitrite (NO2-) and nitrate (NO3-) which are used as inorganic corrosion inhibitors. All theoretical results and experimental inhibition efficiencies of inhibitors were subjected to correlation analyses. In a summary, MP3/SDD level in water was found as the best level. In this level, the inhibition efficiency ranking was found as CrO42- > WO42- > MoO42- > Cr2O72- > NO2- approximate to NO3-. (C) 2013 Elsevier Ltd. All rights reserved.