Ammonium bisulfate

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.

Ammonium bisulfate

Ball-and-stick model of an ammonium cation (left) and a bisulfite anion (right)
Names
IUPAC name Ammonium hydrogen sulfate
Identifiers
CAS Number	7803-63-6 Y
3D model (JSmol)	Interactive image
ChemSpider	23057 Y
ECHA InfoCard	100.029.332
PubChem CID	16211166
RTECS number	WS990000
UNII	6218R7MBZB Y
CompTox Dashboard (EPA)	DTXSID9051244
InChI InChI=1S/H3N.H2O4S/c;1-5(2,3)4/h1H3;(H2,1,2,3,4) Y Key: BIGPRXCJEDHCLP-UHFFFAOYSA-N Y InChI=1/H3N.H2O4S/c;1-5(2,3)4/h1H3;(H2,1,2,3,4) Key: BIGPRXCJEDHCLP-UHFFFAOYAA
SMILES [O-]S(=O)(=O)O.[NH4+]
Properties
Chemical formula	(NH4)HSO4
Molar mass	115.11 g/mol
Appearance	White solid
Density	1.78 g/cm3
Melting point	147 °C (297 °F; 420 K)
Solubility in water	Very soluble
Solubility in other solvents	Soluble in methanol insoluble in acetone
Hazards
NFPA 704 (fire diamond)	3 0 0
Safety data sheet (SDS)	External MSDS
Related compounds
Other anions	Ammonium thiosulfate Ammonium sulfite Ammonium sulfate Ammonium persulfate
Other cations	Sodium bisulfate Potassium bisulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Production

It is commonly collected as a byproduct of the "acetone cyanohydrin route" to the commodity chemical methyl methacrylate.^[1]

It can also be obtained by hydrolysis of sulfamic acid in aqueous solution, which produces the salt in high purity:

H₃NSO₃ + H₂O → (NH₄)HSO₄

It also arises by the thermal decomposition of ammonium sulfate:

(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, known from coal fire environments.^[2][3]