Ammonium tetrafluoroborate (or ammonium fluoroborate) is an inorganic

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...

composed of the

ammonium The ammonium cation is a positively-charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged or protonated substituted amines and quaternary a ...

cation and the tetrafluoroborate anion, with the chemical formula NH₄BF₄. When heated to decomposition, ammonium tetrafluoroborate releases toxic fumes of

hydrogen fluoride Hydrogen fluoride (fluorane) is an inorganic compound with the chemical formula . This colorless gas or liquid is the principal industrial source of fluorine, often as an aqueous solution called hydrofluoric acid. It is an important feedstock i ...

, nitrogen oxides, and

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...

Preparation

Ammonium tetrafluoroborate can be prepared by reacting ammonium fluoride with boric and

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...

: :8 NH₄F + 2 H₃BO₃ + 3 H₂SO₄ → 2 NH₄BF₄ + 3 (NH₄)₂SO₄ + 6 H₂O

References

{{Tetrafluoroborates Ammonium compounds Tetrafluoroborates