New materials useful as electolytic solutes

Ionic compound with low melting point has cation of the onium type with at least one heteroatom such as N, O, S or P; and anion which includes, wholly or partially, at least one imide ion. Independent claims are also included for: (1) electrolytic composition containing this compound; (2) electrochemical generator and capacitor using the composition as electrolyte; (3) modulation system using the composition as electrolyte; and (4) use of the composition in chemical or electrochemical reactions.