GAS-PHASE STRUCTURES OF CHLORINE NITRATE AND BROMINE NITRATE (CLONO2 AND BRONO2)

The gas-phase structure of chlorine nitrate was determined by joint analysis of electron diffraction intensities and rotational constants. The structure of bromine nitrate was derived from electron diffraction data alone. Both nitrates have planar structures, and the following geometric parameters were obtained (r(a) distances in angstroms and angle(alpha) angles in degrees; error limits are 2sigma values and include a possible scale error of 0.1 % for BrONO2): for CIONO2, r(a)(N=O) = 1.196(1), r(a)(N-0) = 1.499(3), r(a)(O-Cl) = 1.673(2), angle(alpha)(O=N=O) = 132.6(5), angle(alpha)(O-N=O(c)) = 118.6(3), angle(alpha)(O-N=O(t)) = 108.8(3), angle(alpha)(N-0-Cl) = 113.0(3);for BrONO2, r(a)(N=O) = 1.205(3), r(a)(N-0) = 1.456(5), r(a)(O-Br) = 1.829(4), angle(alpha)(O=N=O) = 133.9(8), (O-N=O(c)) = 119.5(6), angle(alpha)(O-N=O(t)) = 106.6(5), angle(alpha)(N-O-Br) = 113.9(8). The gas-phase structure for ClONO2 is compared to the crystal structure and to ab initio predictions. The results for both compounds arc discussed together with those of other covalent nitrates XONO2 with X = H, Me, Et, and O2N.