Crystal Structure and Bondcharacter Study in 2, 5 Dichloro-Nitro Benzene by NQR

Abstract

A study of the chlorine nuclear quadrupole resonance has been carried out at room temperature in single crystal of 2, 5 dichloro-nitro benzene. Two field gradients have been found in this crystal, one for each chlorine. The asymmetry parameter values have been determined for both the field gradients. The orientation of the principal axes have been found with respect to the crystallographic axes. Zeeman effect studies have shown that the two molecules in the unit cell are in physically equivalent positions. The molecular plane has been identified as the ‘ab’ plane of the crystal. The determination of the approximate coordinates of the atoms in the crystal is made. The C–Cl bond characters have been determined using the valence bond method. The π electron loss is calculated using Bersohn’s molecular orbital treatment.