Solid state DFT modeling and vibrational characterisation of butylenediammonium and hexylenediammonium hexafluorosilicate, NH^sub 3^(CH^sub 2^)^sub n^NH^sub 3^SiF^sub 6^ (n = 4 and 6)

Experimental and periodic DFT studies of the structural and vibrational (infrared and Raman) properties of two alkylenediammonium hexafluorosilicate compounds, ... and ..., have been performed in crystal phase, where three-dimensional N-H⋯F hydrogen bonds (HB) network was formed. The analysis of the vibrational spectra was supported by factor group analysis, periodic DFT modeling and spectra calculations of 1 and 2 in solid state using the unit cell parameters obtained from the experiment. The analysis of the vibrational spectra was supported by factor group analysis, periodic DFT modeling and spectra calculations of 1 and 2 in solid state using the unit cell parameters obtained from the experiment. The effect of the HB interactions on the geometrical and vibrational characteristics of the ions in the complexes studied was examined. It was shown that the frequencies of the stretching Si-F modes could be used as characteristic spectroscopic data for estimation of the HB relative strength in the series of alkylenediammonium hexafluorosilicate.