Ammonium tetrafluoroborate explained

Ammonium tetrafluoroborate (or ammonium fluoroborate) is an inorganic salt composed of the ammonium cation and the tetrafluoroborate anion, with the chemical formula NH₄BF₄. When heated to decomposition, ammonium tetrafluoroborate releases toxic fumes of hydrogen fluoride, nitrogen oxides, and ammonia.^[1]

Preparation

Ammonium tetrafluoroborate can be prepared by reacting ammonium fluoride with boric and sulfuric acid:^[2]

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

Notes and References

1. Book: Lewis. R. J.. 1997. Sax's Dangerous Properties of Industrial Materials. 9. New York, NY. Van Nostrand Reinhold. 1-3. 209.
2. Web site: Preparation of ammonium fluoroborate. . Prepchem . 26 January 2021.