The crystal structure of α-1,2,4,5-tetrachlorobenzene based on spectroscopic evidence and packing and lattice frequency calculations

The crystal structure of α-l,2,4,5-tetrachlorobenzene has been investigated by spectroscopic methods and packing calculations. With the existing unit-cell parameters, the crystal has been found to belong to space group P with two unrelated molecules located at (0,0,0) and (1/2, 1/2, 0). Atomic positions are given. The structure is closely related to that of the monoclinic βphase. Calculated lattice vibration frequencies are in good agreement with experiment.