Crystal Packing in Equilibrating Systems: A Single Crystal Containing Three Isomers of CuCl(1-pyridin-2-yl-3-p-tolyl-thiourea)2

The X-ray crystal structure of the labile copper(I) complex CuCl(1-pyridin-2-yl-3-p-tolyl-thiourea)2 comprises three different isomers and has profound implications for work on the understanding and prediction of low-symmetry crystal packing. A chloroform co-crystal of one of these isomers is also reported along with a related compound of (6-methyl-benzothiazol-2-yl)-pyridin-2-yl-amine.