Crystal structures of polyiodide salts and molecular complexes. 7. Interaction of thiones with molecular diiodine. The crystal structures of dithizone-diiodine, ethylenethiourea-bis(diiodine), bis(ethylenethiourea)-tris(diiodine), bis(dithizone)-heptakis(diiodine), and 1-(1-imidazolin-2-yl)-2-thioxoimidazolidinium triiodide-(ethylenethiourea-diiodine)