Ionic liquids (IL), ie salts with an organic cation and a low melting point, are in recent decades the most actual liquid systems. This is due to their unique physicochemical properties and application prospects in various fields of science and technology. ILs are widely studied using various experimental techniques and computer simulation methods. Nuclear magnetic resonance (NMR) is one of the most effective methods of studying liquid systems. Ionic liquids represent a favorable target of all three of the main varieties of NMR technique--spectra, relaxation, diffusometry–to obtain extensive and, in many cases, unique information both on the local structure and on the translational and orientation dynamics in these systems.

In the first part of the report the main results reached by NMR for ILs of various types are briefly analyzed. The additional opportunities of the technique in such systems are demonstrated in comparison with normal liquids and solutions of inorganic salts. Characteristic examples of temperature dependences of spin-lattice NMR relaxation of 13C and 1H nuclei for some imidazolium-based ILs are shown. These dependences allow one to obtain information concerning the orientation mobility of the cation functional groups as well as of ions mobility as a whole [1, 2]. Also we demonstrate some errors in interpretation of the experimental relaxation data which were used in earlier published articles. Besides we considered achievements of NMR spectroscopy in the testing of electrolytes, which are promising for use in supercapacitors and other electrochemical devices of new generations. For example, solutions of inorganic salts in so-called “protic” ILs show the effectiveness of the use of NMR to study their local composition and structure [3]. In the second part of the report current ideas are discussed about the heterogeneous structure of some ionic liquids and IL-based liquid systems. We have analyzed the existing data on possible heterogeneity which were obtained by various techniques, including NMR.