HYPOTHETICAL CRYSTAL-STRUCTURES OF BENZENE AT 0 AND 30 KBAR

Possible crystal structures of benzene were generated without any prio r crystallographic information, using a systematic grid search method. Only structures with one molecule in the asymmetric unit were conside red. 31 space groups were investigated, and the resulting structures w ere clustered and checked for stability upon removal of the space-grou p symmetry. In the enthalpy range similar to 10 kJ mol(-1) 30 structur es were found at zero pressure and 20 structures at a pressure of 30 k bar. Their pressure-dependent rankings and interconversions are discus sed. The results are compared to previous, less complete, investigatio ns. A possible structure for the high-pressure phase benzene (II), on which only limited powder diffraction data have been published, is sug gested.