Synthesis and Characterization of Poly(hydrogen halide) Halogenates (-I).

: Herein we report the synthesis and characterization of a variety of novel poly(hydrogen halide) halogenates (-I). The bifluoride ion, which is known to have the highest hydrogen bond energy of 160 kJ mol -1 , is the most famous among many examples of [X(HX) n ] - anions (X = F, Cl) known in the literature. In contrast, little is known about poly(hydrogen halide) halogenates containing two different halogens, ([X(HY) n ] - ). In this work we present the synthesis of anions of the type [X(HY) n ] - (X = Br, I, ClO 4 ; Y = Cl, Br, CN) stabilized by the [PPh 4 ] + and [PPN] + cation. The obtained compounds have been characterized by single-crystal X-ray diffraction, Raman spectroscopy and quantum-chemical calculations. In addition, the behaviour of halide ions in hydrogen fluoride was investigated using experimental and quantum-chemical methods in order to gain knowledge on the acidity of hydrogen halides in HF.