The Nature of the 1600 cm−1Band of Carbons

Since what appears to be the first infrared (IR) observation of a char by Kmetko in 1951,1 IR spectra of coals, chars and various carbon materials have been invariably shown to have a more or less intense band near 1600 cm−1. A variety of suggestions has been made concerning the cause of the band but the assignments have been in dispute and remained controversial for thirty years.