The program IRPal is a powerful tool for the interpretation of IR-spectra of organic compounds. It not only gives the user one or more functional groups that feature absorption band(s) for a selected wavenumber, but relates that information to the possible existence of other bands in the spectrum that could confirm these assignments.

Thus, if we assign a peak at 1700 cm-1 to a carbonyl stretch of an aromatic aldehyde the program prompts the user to check the presence of aldehyde C-H at 2720 and 2820 cm-1 and a number of typical aromatic C-H out of plane bands. Apart from this, one can rule out classes of compounds by making them invisible to the user.

If a sample is known not to contain nitrogen, one can hide all amine, amide, nitrile, etc. data thereby facilitating structure elucidation. Assignments can be logged and annotated and imported into other applications. The program also features graphical representation of the data given in the tables.