Abstract
Two radical species were formed when malonamide crystals were irradiated with x ray. One was a π‐electron radical of common occurrence, NH2COĊHCONH2, and the other was interpreted as a σ‐electron radical of the formula NH2COĊH2COṄH. The ESR spectra of the latter were studied in detail and the assignments were substantiated by ESR spectra of deuterated malonamide and 15N‐malonamide.