Proton conducting system (ImH2)2SeO4·2H2O investigated with vibrational spectroscopy

•Spectral investigation of imidazolium selenate dihydrate has been carried out.•Spectral analysis provides the information of the hydrogen bond network.•The bond critical points analysis reveal the structure for medium hydrogen bonds.•The high value of conductivity is based on the Grotthus-type mechanism.

Imidazolium selenate dihydrate (ImH2)2SeO4·2H2O crystals have been investigated using Raman and IR spectroscopy. Experimental data were supported by the quantum-chemical calculations (DFT), Hirshfield surfaces and fingerprint plots analysis, and Bader theory calculations. The imidazolium selenate dihydrate crystal exhibits high proton conductivity of the order of ~ 10− 1 S/m at T = 333 K. The spectra of this compound are dominated by bands related to the lattice modes, the internal vibrations of the protonated imidazole cation, selenate anion, water molecules, and hydrogen bonds network. For the imidazolium selenate dihydrate crystal, the formal classification of the fundamental modes has been carried out.

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