PHASE-TRANSFORMATION AND STRUCTURE OF N-CHLOROCARBONYLISOCYANIDE DICHLORIDE

The Cl-35 nuclear quadrupole resonances in N-chlorocarbonylisocyanide dichloride show that it exists in two polymorphic forms. The metastabl e alpha phase has six Cl-35 NQR lines and the stable beta phase has th ree. The latter is obtained irreversibly by annealing the alpha phase at 179 K. The temperature dependences of the Cl-35 NQR frequencies, sp in-lattice and spin-spin relaxation times are obtained in both phases. The results of the Cl-35 NQR studies are discussed together with calc ulated MNDO level data and other physical properties (IR frequencies, dipole moments) of this compound.