INFRARED-SPECTRA OF THE M+BRF2-ION AND M+IF2-ION PAIRS IN SOLID ARGON

Infrared absorptions for the trihalide anions BrF2- and IF2- have been observed in experiments codepositing an argon/fluorine mixture and the alkali bromide and alkali iodide salt vapors onto a cesium iodide window at 15 K. Infrared bands in the 520-530-cm-1 region and the 360-365-cm-1 region are assigned to the symmetric FBrF- and asymmetric BrFF- species, respectively, in the M+BrF2-ion pair. In the alkali iodide experiments, the analogous bands were observed in the vicinity of 505 cm-1 for M+FIF-and near 355 cm-1 for M+IFF-. In most experiments, a band was observed at 550 cm-1 which has been previously assigned to the M+F3- species, a product of the secondary reaction of MF with fluorine. These results are compatible with the following reaction scheme:[FORMULA OMMITED] Salt reactions with HF impurity also produced the M+FHX- bihalide complexes. © 1979, American Chemical Society. All rights reserved.