Theoretical investigation of the structures, stabilities and vibrational properties of triatomic interhalide ions and their alkali ion pairs
Frenio A. Redeker, Alexey Kropman, Carsten Müller, Sarah E. Zewge, Helmut Beckers, Beate Paulus, Sebastian Riedel – 2018
While homonuclear free trihalide anions and their alkali ion pairs have been thoroughly described experimentally and theoretically, the coverage of their heteronuclear relatives in the literature remains fragmentary. This might be merely a consequence of the large variety of possible compositions of trihalide anions, however the experimental difficulties associated with the preparation of heteronuclear trihalide anions especially those containing the lightest halogen atom F could also play a role. This paper is a systematic approach to a complete theoretical description of the free inter trihalide anions XXX⁻, XXY⁻, YXY⁻, and XYZ⁻ (X, Y, Z = F–I) and their alkali ion pairs MXXX, MYXX, MXXY, MYXY, and MXYZ (M = Li–Cs; X, Y, Z = F–Br). The minimum structures obtained from calculations at CCSD(T)/triple-ζ level of theory were analyzed and ordered with respect to trends in their structural appearance, dissociation energies, and vibrational properties. Predictions about the existence of mixed alkali trihalide anions and new insights about existing experimental data could be derived from calculated data.