Hydroxylammonium sulfate

Hydroxylammonium sulfate is the inorganic compound with the formula [NH₃OH]₂SO₄. A colorless solid, it is the sulfate salt of hydroxylamine. It is primarily used as an easily handled form of hydroxylamine, which is a volatile liquid.^[2]

Hydroxylammonium sulfate

Names
Other names Hydroxylamine sulfate
Identifiers
CAS Number	10039-54-0 Y
3D model (JSmol)	Interactive image
ChEMBL	ChEMBL3183215
ChemSpider	23229 Y
ECHA InfoCard	100.030.095
EC Number	233-118-8
PubChem CID	24846
RTECS number	NC5425000
UNII	49KP498D4O Y
UN number	2865
CompTox Dashboard (EPA)	DTXSID2025424
InChI InChI=1S/2H4NO.H2O4S/c2*1-2;1-5(2,3)4/h2*2H,1H3;(H2,1,2,3,4)/q2*+1;/p-2 Y Key: VGYYSIDKAKXZEE-UHFFFAOYSA-L Y InChI=1/2H4NO.H2O4S/c2*1-2;1-5(2,3)4/h2*2H,1H3;(H2,1,2,3,4)/q2*+1;/p-2 Key: VGYYSIDKAKXZEE-NUQVWONBAN
SMILES [O-]S([O-])(=O)=O.O[NH3+].O[NH3+]
Properties
Chemical formula	H8N2O6S
Molar mass	164.14 g/mol
Appearance	white crystalline to fine product, slightly hygroscopic
Density	1.88 g/cm3
Melting point	120 °C (248 °F; 393 K) decomposes
Solubility in water	58.7 g/100 ml (20 °C)
Structure[1]
Crystal structure	Monoclinic
Space group	P21/c
Lattice constant	a = 7.932±0.002 Å, b = 7.321±0.002 Å, c = 10.403±0.003 Å α = 90°, β = 106.93±0.03°, γ = 90°
Formula units (Z)	4
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H290, H302, H312, H315, H317, H319, H351, H373, H400, H412
Precautionary statements	P201, P202, P234, P260, P261, P264, P270, P272, P273, P280, P281, P301+P312, P302+P352, P305+P351+P338, P308+P313, P312, P314, P321, P322, P330, P332+P313, P333+P313, P337+P313, P362, P363, P390, P391, P404, P405, P501
NFPA 704 (fire diamond)	3 1 2
Safety data sheet (SDS)	External MSDS
Related compounds
Other anions	Hydroxylammonium nitrate Hydroxylammonium chloride
Other cations	Ammonium sulfate Hydrazinium sulfate
Related compounds	Hydroxylamine
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is YN ?) Infobox references

Production

Hydroxylammonium sulfate is prepared industrially by protonation of hydroxylamine. The latter is produced by the hydrogenation of nitric oxide using a platinum catalyst:^[2]

2 NO + 3 H₂ + H₂SO₄ → [NH₃OH]₂[SO₄]

Another route to NH₂OH is the Raschig process: aqueous ammonium nitrite is reduced by HSO−3 and SO₂ at 0 °C to yield a hydroxylamido-N,N-disulfonate anion::^[3]

[NH₄]⁺[NO₂]⁻ + 2 SO₂ + NH₃ + H₂O → [NH₄]₂[HON(SO₃)₂]

This ammonium hydroxylamine disulfonate anion is then hydrolyzed to give hydroxylammonium sulfate:

[NH₄]₂[HON(SO₃)₂] + 2 H₂O → [HONH₃]₂SO₄

Applications

Main article: Hydroxylamine § Reactions

Almost all hydroxylamine and its salts are used to make precursors to nylons via cyclohexanone oxime.^[2] Many aldehydes and ketones undergo the same conversion to oximes. carboxylic acids and their derivatives (e.g. esters) convert to hydroxamic acids. Isocyanates to N-hydroxyureas. Nitriles react to give amidoximes. Hydroxylammonium sulfate is also used to generate hydroxylamine-O-sulfonic acid from oleum or from chlorosulfuric acid.

Hydroxylammonium sulfate is used in the production of anti-skinning agents, pharmaceuticals, rubber, textiles, plastics and detergents. It is a radical scavenger that terminates radical polymerization reactions and serves as an antioxidant in natural rubber. (NH₃OH)₂SO₄ is a starting material for some insecticides, herbicides and growth regulators. It is used in photography as a stabiliser for colour developers and as an additive in photographic emulsions in colour film.

Structure

Hydroxylammonium sulfate exists as tetrahedral NH₃OH⁺ cations and sulfate anions.

Safety

Hydroxylamine, which occurs widely in nature, has low toxicity. The compound is stable below 120 °C.^[2]