Construction of Ternary Iodine–Bromine–Chlorine Octahalides

A series of five ternary octanuclear iodine‐bromine‐chlorine interhalides, [I 2 Br 2 Cl 4 ] 2− ( 1 ), [I 3 BrCl 4 ] 2− ( 2 ), [I 4 Br 2 Cl 2 ] 2− ( 3 ), [I 2 Br 4 Cl 2 ] 2− ( 4 ) and [I 3 Br 3 Cl 2 ] 2− ( 5 ), have been rationally constructed in two steps. Firstly, addition of a dihalogen (ICl or IBr) to the triaminocyclopropenium chloride salt [C 3 (NEt 2 ) 3 ]Cl forms the corresponding trihalide salt with [ICl 2 ] − or [BrICl] − anions, respectively. Secondly, addition of a half‐equivalent of a second dihalogen, followed by crystallization at low temperature, gives the corresponding octahalide: addition of Br 2 and IBr to [ICl 2 ] − gives 1 and 2 , respectively, whereas addition of I 2 , Br 2 and IBr to [BrICl] − gives 3 , 4 and 5 , respectively. The five octahalides were characterized by X‐ray crystallography and far–IR spectroscopy.