TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Salt: The alkali metal salt is a lithium salt. SPECIFIC COMPOUNDS - The boron compound of formula (I) is tris(2,3,4,6-tetrafluoro phenyl) borane, tris(2,3,5,6-tetrafluoro phenyl) borane, tris(2,3,5-trifluoro phenyl) borane or tris(2,4,6-trifluoro phenyl) borane (disclosed).    EXAMPLE - Diethyl ether (in g) (49.7) and boron trifluoride diethyl ether complex (8.385) were prepared in a reaction container. Diethyl ether solution containing 0.177 mole of pentafluorophenyl magnesium bromide (90 ml) was prepared. The diethyl ether solution was dropped in at room temperature for 75 minutes and the boron compound solution was stirred under nitrogen gas atmosphere. The reaction solution was stirred for 3 hours and reacted with reflux temperature under nitrogen. Diethyl ether solution of tris (pentafluorophenyl) borane was obtained.    Isopar E (hydrocarbon based solvent) (250) was prepared in a distillation container and diethyl ether solution of tris (pentafluorophenyl) borane was prepared. The temperature was raised to 90 degrees C under nitrogen gas with stirring. Diethyl ether solution was dropped in for 15 minutes and diethyl ether was distilled. The temperature of contents (mixture) in the container was raised to 125 degrees C and diethyl ether was distilled. The contents were cooled to 90 degrees C and filtration was performed to remove fluorinated magnesium bromide. The tris (pentafluorophenyl) boron without magnesium bromide was obtained.    Isopar E solution was cooled to room temperature and filtration was performed. The crystal was removed and dried under reduced pressure at room temperature, and tris (pentafluorophenyl) borane/bis (pentafluorophenyl) borane/(pentafluoro phenyl) borane compound was obtained. The purity of tris (pentafluorophenyl) borane and bis (pentafluorophenyl) borane were 98.2 mol% and 1.8 mol%, respectively. The quantity of residual diethyl ether with respect to the tris (pentafluorophenyl) borane was 45 mol%.    Lithium hexafluorophosphate was dissolved in non-aqueous solvent (mixture of propylene carbonate and dimethoxy ethane in a ratio of 1:1) and electrolyte solution in a concentration 1 mol/l was obtained. Tris (pentafluorophenyl) borane/bis(pentafluoro phenyl) borane/(pentafluoro phenyl) borane compound (0.1 mole) was added to the electrolyte solution and dissolved completely. Ionic conductive material was obtained. The material had ionic conductivity of 3.21x10(-2)S/cm.