Ammonium bisulfate, also known as ammonium hydrogen sulfate, is a white, crystalline solid with the formula (NH₄)HSO₄. This salt is the product of the half-neutralization of sulfuric acid by ammonia.

Production

It is commonly collected as a byproduct of the "acetone cyanohydrin route" to the commodity chemical methyl methacrylate. It can also be obtained by hydrolysis of

sulfamic acid Sulfamic acid, also known as amidosulfonic acid, amidosulfuric acid, aminosulfonic acid, sulphamic acid and sulfamidic acid, is a molecular compound with the formula H3NSO3. This colourless, water-soluble compound finds many applications. Sulfami ...

in aqueous solution, which produces the salt in high purity: : H₃NSO₃ + H₂O → H₄sup>+ SO₄sup>− It also arises by the thermal decomposition of

ammonium sulfate Ammonium sulfate (American English and international scientific usage; ammonium sulphate in British English); (NH4)2SO4, is an inorganic salt with a number of commercial uses. The most common use is as a soil fertilizer. It contains 21% nitrogen a ...

: : (NH₄)₂SO₄ → (NH₄)HSO₄ + NH₃

Applications

It can be further neutralized with ammonia to form ammonium sulfate, a valuable fertilizer. It can be used as a weaker alternative to sulfuric acid, although sodium bisulfate is much more common.

Natural occurrence

A related compound of the (NH₄)₃H(SO₄)₂ formula, occurs as the rare mineral

letovicite Letovicite () is an ammonium sulfate mineral with composition (NH4)3H(SO4)2 (IUPAC: triammonium sulfate hydrogensulfate, Nickel–Strunz classification 07.AD.20). It is a rare colorless or white monoclinic secondary mineral formed during the burn ...

, known from coal fire environments.

References

{{inorganic-compound-stub Ammonium compounds Sulfates