Journal of Chemical Sciences

, Volume 96, Issue 6, pp 599–605

The chloro-methyl exchange rule and its violations in the packing of organic molecular solids

  • Gautam R Desiraju
  • Jagarlapudi A R P Sarma

DOI: 10.1007/BF02936309

Cite this article as:
Desiraju, G.R. & Sarma, J.A.R.P. Proc. Indian Acad. Sci. (Chem. Sci.) (1986) 96: 599. doi:10.1007/BF02936309


Since chloro and methyl groups have nearly the same volume, they may be interchanged in a molecule without altering the crystal structure. Such isostructural behaviour is found when crystal stabilization is mainly through dispersive and repulsive interactions. Violations of this rule are, however, observed when directional forces or weak bonds are involved and the failure of complete chloro-methyl exchange in a substance like hexachlorobenzene, points to the importance of weakly attractive Cl...Cl interactions.


Chloro-methyl exchangecrystal engineeringclose-packinghexachlorobenzeneCl...Cl interactions

Copyright information

© Indian Academy of Sciences 1986

Authors and Affiliations

  • Gautam R Desiraju
    • 1
  • Jagarlapudi A R P Sarma
    • 1
  1. 1.School of Chemistry, University of HyderabadP. O. Central UniversityHyderabadIndia