The infrared spectra of the salts of nitro compounds. Characteristic frequencies of the carbonitronate group, CNO2−

The infrared spectra of salts of nitro compounds have been studied and the N-O asymmetric and symmetric stretchings of the carbonitronate ion have been assigned to the regions 1316–1205 and 1175–1040 cm−1. The CN frequency of sodium alkanenitronates appears in the region 1605–1587 cm−1. The carbonyl and the nitrile stretching frequencies in α-nitroketones and α-nitronitriles are considerably reduced due to conjugation with the carbonitronate group.