Knowledge Bank

The ESR spectra of three radical species have been observed near g = 2 in powder and single crystal samples of dicyandiamide (cyanoguanidine). ($NH2)2C2NCN$. One of the spectra is a broad line of width 8 G. The other spectra each show interaction of an unpaired electron with one proton and one $N14$ nucleus. One radical, with $aH$ = 29 G and $aN$ = 16 G is a $\pi$-electron radical whereas the other, with $aH$ = 72.5 G and $aN$ = 6 G appears to be a $\pi$-electron radical. The origin of the radicals in relation to the atom positions in the undamaged dicyandiamide crystal will be discussed.