A method of purifying lithium hexafluorophosphate that allows to purify lithium
hexafluorophosphate, useful as lithium secondary cell electrolyte, organic synthesis
medium or the like, to an extremely high purity is provided. Lithium hexafluorophosphate
containing harmful impurities such as oxyfluoride, lithium fluoride is purified
by adding phosphoric chloride. The purification is performed in the presence of
phosphoric chloride and hydrogen fluoride of the quantity equal or superior to
the equivalent amount for reacting them, and then by converting lithium fluoride
lithium hexafluorophosphate with generated phosphor pentafluoride.
