A new polymorph of phenylselenium trichloride.

A second polymorph of phenylselenium trichloride, PhSeCl or CHClSe, is disclosed, which is comprised of asymmetric chlorine-bridged noncovalent dimer units rather than polymeric chains. These dimers are each weakly bound to an adjacent dimer through noncovalent Se...Cl bonding interactions. Phenyl rings within each dimer are oriented in a syn fashion. Density functional theory (DFT) calculations reveal that the putative anti isomer is within 5 kJ mol of the experimentally observed form. This structure represents the first additional polymorph discovered for an organoselenium trihalide compound.