Electronic parameters such as HOMO-LUMO energies, Mulliken charges, dipole moments for different isomers of SF4, SF4O, PCl4F, PCl3F2, PCl2F3, PCl2F4 molecules have been carried out at the MP2 level of theory using 6-31G(d), 6-311G(d,p) basis sets by applying Gaussian 03 Revision B-04. Maximum hardness and minimum polarizability have been calculated to see the consistency with the Bent rule. According to Maximum Hardness Principles (MHP) and Minimum Polarizability Principles (MPP) most stable structure can be predicted if they have different isomers. We have investigated how bond orbitals change for studied molecules by natural bond orbital (NBO) analysis, as well. There is agreement between our results and experimentaql results on the dipole moments and structures of the phosphorus chlorofluorides obtained by IR and Raman vibrational data, NMR measurements and Cl-35 pure quadrupole resonance frequencies reported earlier by Holmes aand coworkers.