Abstract: A solution containing an organic solvent and a compound including impurities, represented by, for example, general formula (1) (wherein R1 to R10 independently represent H, F, a hydrocarbon group or an alkoxy group, at least one of R1 to R5 is F, at least one of R6 to R10 is F, M is H, alkali metal, alkaline earth metal or alkaline earth metal halide, n is 3 or 4, and m is 2 when M is an alkaline earth metal, or m is 1 when M is the other) is mixed with water. The purified compound is reacted with a compound which forms a monovalent cation seed to prepare a derivative. Thus, a purifying method capable of efficiently and easily separating and removing colored components contained in tetrakis(fluoroaryl)borate compounds can be provided. Moreover, it is possible to provide a method capable of preparing a highly-pure tetrakis(fluoroaryl)borate derivative efficiently and at low costs.

Abstract: In order to provide a method of safely, efficiently, and industrially manufacturing fluoroaryl magnesium halide containing no impurities, such as coloring components, by a relatively gradual reaction compared with the conventional reactions, and a method of readily and efficiently manufacturing a highly-pure fluoroaryl borane derivative, fluoroaryl magnesium halide expressed by General Formula (1): where each of R1-R5 independently represents H, F, a hydrocarbon group, or an alkoxy group, provided that at least three of R1-R5 are fluorine atoms, and Xa represents Cl, Br, or I; is manufactured by reacting, in a solvent containing a chain ether solvent, hydrocarbon magnesium halide expressed by General Formula (2): R6MgXa  (2) where R6 represents a hydrocarbon group, and Xa represents Cl, Br, or I; with fluoroaryl halide expressed by General Formula (3): where each of R1-R5 independently represents H, F, a hydrocarbon group, or an alkoxy group, provided that at