The vibrational spectrum of ortho-phosphoric acid in some non-aqueous solvents

The infra-red spectrum of ortho-phosphoric and deutero ortho-phosphoric acids have been measured in acetonitrile, dioxan, acetone and tetrahydrofuran. The frequencies associated with the symmetric PO and PO stretching vibrations are observed to move apart from their observed frequencies in aqueous solutions. The observed data is shown to be consistent with accepted values of force constants for PO and PO bonds. There is uncertainty in the frequency of the lowest e fundamental.