Armand Budzianowski and Andrzej Katrusiak
Acta Crystallographica Section B
Volume 62, Part 1 (February 2006)
Acta Cryst. (2006). B62, 94-101 [doi:10.1107/S010876810503747X]
Authorised by IUCr electronic reprint of the article
The crystal structure of benzene, C6H6, in situ pressure-frozen in phase I, has been determined by X-ray diffraction at 0.30, 0.70 and 1.10GPa, and 296K. The molecular aggregation within phase I is consistent with van der Waals contacts and electrostatic attraction of the positive net atomic charges at the H atoms with the negative net charges of the C atoms. The C-Haromatic ring centre contacts are the most prominent feature of the two experimentaly determined benzene crystal structures in phases I and III, whereas no stacking of the molecules has been observed. This specific crystal packing is a likely reason for the exceptionally high polymerization pressure of benzene. The changes of molecular arrangement within phase I on elevating the pressure and lowering the temperature are analogous.