Nontypical iodine-halogen bonds in the crystal structure of (3E)-8-chloro-3-iodomethylidene-2,3-dihydro-1,4-oxazino[2,3,4-ij]quinolin-4-ium triiodide

Two kinds of iodine–iodine halogen bonds are the focus of our attention in the crystal structure of the title salt, C12H8ClINO+·I3−, described by X‐ray diffraction. The first kind is a halogen bond, reinforced by charges, between the I atom of the heterocyclic cation and the triiodide anion. The second kind is the rare case of a halogen bond between the terminal atoms of neighbouring triiodide anions. The influence of relatively weakly bound iodine inside an asymmetric triiodide anion on the thermal and Raman spectroscopic properties has been demonstrated. A new dihydrooxazinoquinolinium triiodide has been synthesized and characterized by single‐crystal X‐ray diffraction analysis, Raman spectroscopy and thermal analysis. The iodine–iodine halogen bonds formed between neighbouring triiodide anions and between triiodide anions and iodine‐containing heterocyclic cations are the basis of the noncovalent interactions in the analyzed crystal.