Hydroxylammonium sulfate

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Hydroxylammonium sulfate
Other names
Hydroxylamine sulfate
3D model (JSmol)
ECHA InfoCard 100.030.095
EC Number 233-118-8
RTECS number NC5425000
UN number 2865
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
58.7 g/100 ml (20 °C)
Safety data sheet External MSDS
Explosive (E)
Carc. Cat. 3
Toxic (T)
Harmful (Xn)
Irritant (Xi)
Dangerous for the environment (N)
R-phrases (outdated) R2, R21/22, R36/38, R40, R43, R48/22, R50
S-phrases (outdated) (S2), S36/37, S61
NFPA 704
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oilHealth code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gasReactivity code 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g., phosphorusSpecial hazards (white): no codeNFPA 704 four-colored diamond
Related compounds
Other anions
Hydroxylammonium nitrate
Hydroxylammonium chloride
Other cations
Ammonium sulfate
Hydrazinium sulfate
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Hydroxylammonium sulfate (NH3OH)2SO4, is the sulfuric acid salt of hydroxylamine. It is primarily used as an easily handled form of hydroxylamine, which is explosive when pure.


Hydroxylammonium sulfate can be obtained by the acid-base reaction of hydroxylamine with sulfuric acid:

2NH2OH(aq) + H2SO4(aq) → (NH3OH)2SO4(aq)


Hydroxylammonium sulfate is used in organic synthesis to convert aldehydes and ketones to oximes, carboxylic acids and their derivatives (e.g. esters) to hydroxamic acids, isocyanates to N-hydroxyureas and nitriles to amidoximes. Hydroxylammonium sulfate is also used to generate hydroxylamine-O-sulfonic acid from oleum or 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.


At 120 °C, hydroxylammonium sulfate begins to decompose to sulfur trioxide, nitrous oxide, water, and ammonia:

2(NH3OH)2SO4 → 2SO3 + N2O + 2NH3 + 5H2O

The reaction is exothermic above 138 °C, and is most exothermic at 177 °C.[1] Metals (especially copper, its alloys and its salts) catalyse the decomposition of hydroxylammonium sulfate. The instability of this compound is mainly due to the hydroxylammonium ion's weak nitrogen to oxygen single bond.


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