Sodium fluoroborate (sodium tetrafluoroborate) is an inorganic compound with the formula NaBF4. It is used in the sand casting of aluminum, electrochemical processes, and as fluorinating agent. It is also used as an additive in chrome, nickel and cadmium plating baths. Sodium tetrafluoroborate may be used as a catalyst for the synthesis of bis(indolyl)methanes via electrophilic substitution reaction of indoles with aldehydes and ketones. It may also be used as a source of tetrafluoroborate anoins during the synthesis of ionic liquids like 1-butyl-3-methylimidazolium tetrafluoroborate[4] and trihexyl(tetradecyl)phosphonium tetrafluoroborate.