Computational study on molecular structure, vibrational spectrum analysis and acidity strength of P4On (n = 6-10) phosphorus oxides with cage structure

In this study, molecular structure, IR spectra and acidity strength of P4On (n = 6-10) type phosphorus oxides with cage structure were investigated at the PBE1PBE/6-311+G(2d) level. Structural parameters and IR spectra of oxides were obtained from optimized structures. From the structural parameters and IR spectra, P4O6 and P4O10 molecules were found in Td symmetry, P4O7 and P4O9 molecules in C3v symmetry and P4O8 molecule in C2v symmetry. Symmetry labeling of the peaks in the IR spectra of oxides was performed.To predict the acidity strength of the oxides in the gas phase, the protonated species were optimized at the PBE1PBE/6-311+G(2d) level. Proton affinity values were calculated using the total energies of neutral and protonated species. Acidity strength ranking according to proton affinity values was obtained as P4O6 < P4O7 < P4O8 < P4O9 < P4O10.