Sodium tetrafluoroborate is an inorganic compound with formula NaBF4.

It is a salt that forms colorless or white rhombic crystals and is soluble in water (108 g/100 mL) but less soluble in organic solvents.

[1] Sodium tetrafluoroborate is used in some fluxes used for brazing and to produce boron trifluoride.

[3] Alternatively the chemical can be synthesized from boric acid, hydrofluoric acid, and sodium carbonate:[2] On heating to its melting point, sodium tetrafluoroborate decomposes to sodium fluoride and boron trifluoride:[4] It is a source of tetrafluoroborate anion, which is used in organic chemistry for the preparation of salts.

Sodium tetrafluoroborate can be used for synthesis of ionic liquids, where tetrafluoroborate is the anion.