An accidental discovery of a new mixed-valent iodine compound - Crystal structure of difluoroiodato(V) iodine(III) dichloride [Cl2IOI(O)F-2]

The crystal structure of the novel iodine compound Cl2IOI(O)F-2 is describe d. Cl2IOI(O)F-2 contains iodine in two different oxidation states (III) and (V) and can formally be described as ICl2+IF2O2-, linked by an unsymmetric al, non-linear I-O-I bridge, with I-O bond lengths of 1.84(1) Angstrom and 2.32(1) Angstrom, and a bond angle of 122.5(5)degrees. It was accidentally obtained by the uncontrolled reaction between CF3I, CF3OCl, CF2O, and Cl-2 at -70 degreesC over a period of about six months and finally two days at r oom temperature. Cl2IOI(O)F-2 crystallises in the monoclinic space group P2 (1)/c with four formula units per unit cell with the dimensions a = 12.910( 1), b = 6.987(1), c = 7.550(1) Angstrom, and beta = 94.890(1)degrees. The m olecule was additionally characterised by its Raman and IR spectra.