Ammonium hydroxide

Athanor · official

H₅NO · 35.046 g/mol

IUPAC name: azanium hydroxide

Also called ammonia solution, aqua ammonia

Inorganic

Open in Athanor

Drawn from its SMILES with RDKit

DangerCauses severe skin burns and eye damage · Very toxic to aquatic life

Names and identifiers

IUPAC name: azanium hydroxide
Synonyms: ammonia solution, aqua ammonia, Ammonia water
+ 37 more
Ammonia aqueous, Aquammonia, Ammonia, aqua, Household ammonia, NH4OH, Ammonia, monohydrate, Ammonia water 29%, SX 1 (ammonia water), Ammonium hydroxide ((NH4)(OH)), DTXSID4020080, CHEBI:18219, Hydroxide, Ammonium, RefChem:6613, DTXCID8080, 921-933-8, Ammonium hydrate, Ammoniumhydroxid, MFCD00066650, Caswell No. 044, ammoniumhydroxide, Ammonia, aqueous, SX 1, Ammonia water [JAN], HSDB 5125, EINECS 215-647-6, UN2672, UN3318, EPA Pesticide Chemical Code 005301, ammoniaque, ammonia hydrate, water ammonia, ammonium hydoxide, ammonium hydroxid, ammonium hyroxide, amonium hydroxide, agua de amoniaco, ammonium hydorxide
Molecular formula: H₅NO
Empirical formula: H₅NO
Molecular weight: 35.046 g/mol
Exact mass: 35.03711
CAS number: 1336-21-6
PubChem CID: 14923
Canonical SMILES: [NH4+].[OH-]
Isomeric SMILES: [NH4+].[OH-]
InChI: InChI=1S/H3N.H2O/h1H3;1H2
InChIKey: VHUUQVKOLVNVRT-UHFFFAOYSA-N
Molfile

Names, InChI and the identifiers from PubChem, retrieved 2026-10-14.

Physical properties

TemperaturePressureDensity

Appearance: Ammonium hydroxide appears as a colorless aqueous solution. Concentration of ammonia ranges up to approximately 30%. Ammonia vapors (which arise from the solution) irritate the eyes.[1]
3 values
From CAMEO Chemicals, the most authoritative source here.
Value As written Source
–shown Ammonium hydroxide appears as a colorless aqueous solution. Concentration of ammonia ranges up to approximately 30%. Ammonia vapors (which arise from the solution) irritate the eyes. [1] CAMEO Chemicals
– Liquid; Other Solid; Liquid; CBI; Other Solid; Gas Vapor [2] EPA Chemical Data Reporting (CDR)
– VERY VOLATILE COLOURLESS AMMONIA SOLUTION IN WATER WITH PUNGENT ODOUR. [3] ILO-WHO International Chemical Safety Cards (ICSCs)
Melting point: -58 °C (25%)[3]
2 values
Sources disagree; from ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative.
Value As written Source
−58 °Cshown -58 °C (25%) [3] ILO-WHO International Chemical Safety Cards (ICSCs)
−77 °C -77 °C [5] PAC Chemical Database, U.S. Department of Energy
Boiling point: 38 °C (25%)[3]
2 values
Sources disagree; from ILO-WHO International Chemical Safety Cards (ICSCs), the most authoritative.
Value As written Source
38 °Cshown 38 °C (25%) [3] ILO-WHO International Chemical Safety Cards (ICSCs)
36 °C 36 °C @760 [mm Hg] [5] PAC Chemical Database, U.S. Department of Energy
Density: Relative density (water = 1): 0.9 (25%)[3]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
–shown Relative density (water = 1): 0.9 (25%) [3] ILO-WHO International Chemical Safety Cards (ICSCs)
– 0.9 @25 °C [5] PAC Chemical Database, U.S. Department of Energy
Solubility in water: Solubility in water: miscible[3]
Vapor pressure: 2160 mmHg @ 25 °C[4]
2 values
2 of 2 sources agree on it (most common value).
Value As written Source
2160 mmHgshown 2160 mm Hg @ 25 °C [4] Hazardous Substances Data Bank (HSDB)cites Daubert, T.E., R.P. Danner. Physical and Thermodynamic Properties of Pure Chemicals Data Compilation. Washington, D.C.: Taylor and Francis, 1989.
2160 mmHg 2160 [mm Hg] @25 °C [5] PAC Chemical Database, U.S. Department of Energy
1 more value was reported but failed the checks (unreadable or out of range), so it is not shown.

Value	As written	Source
–shown	Ammonium hydroxide appears as a colorless aqueous solution. Concentration of ammonia ranges up to approximately 30%. Ammonia vapors (which arise from the solution) irritate the eyes.	[1] CAMEO Chemicals
–	Liquid; Other Solid; Liquid; CBI; Other Solid; Gas Vapor	[2] EPA Chemical Data Reporting (CDR)
–	VERY VOLATILE COLOURLESS AMMONIA SOLUTION IN WATER WITH PUNGENT ODOUR.	[3] ILO-WHO International Chemical Safety Cards (ICSCs)

Value	As written	Source
−58 °Cshown	-58 °C (25%)	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
−77 °C	-77 °C	[5] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
38 °Cshown	38 °C (25%)	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
36 °C	36 °C @760 [mm Hg]	[5] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
–shown	Relative density (water = 1): 0.9 (25%)	[3] ILO-WHO International Chemical Safety Cards (ICSCs)
–	0.9 @25 °C	[5] PAC Chemical Database, U.S. Department of Energy

Value	As written	Source
2160 mmHgshown	2160 mm Hg @ 25 °C	[4] Hazardous Substances Data Bank (HSDB)cites Daubert, T.E., R.P. Danner. Physical and Thermodynamic Properties of Pure Chemicals Data Compilation. Washington, D.C.: Taylor and Francis, 1989.
2160 mmHg	2160 [mm Hg] @25 °C	[5] PAC Chemical Database, U.S. Department of Energy

Each value as its source reports it, with the source's number after it (listed under References). Where several sources report a property, the row shows the value most of them agree on, the rule the app uses; open the values to see every one.

Calculated

Heavy atoms: 2
Rings: 0
Aromatic rings: 0
Fraction sp³ carbons (Fsp3): 0
H-bond donors: 1 computed here · PubChem 2
H-bond acceptors: 1
Rotatable bonds: 0
TPSA (Å²): 66.5 computed here · PubChem 2
Formal charge: 0
Complexity: 0 PubChem
Stereocenters: None
Double-bond geometry: None specified
Point group: C1 of one 3D conformer with its hydrogens, by Athanor’s engine (as in the app)

Elemental analysis

H14.38%
N39.97%
O45.65%

Isotope pattern

Each peak is a nominal mass with its abundance-weighted exact mass, as a percentage of the tallest, from IUPAC natural isotope abundances.

Computed from the structure with RDKit 2026.09 when this page was built, beside PubChem's own computed values from its record; where the two differ, both are shown.

Predicted

log P: 0.2 Crippen (Wildman and Crippen 1999)
log S (water solubility): -0.18 ESOL (Delaney 2004), log mol/L
Synthetic accessibility: 8.49 SA score, 1 easy to 10 hard (Ertl and Schuffenhauer 2009)

Drug-likeness: Lipinski’s rule of five

Molecular weight ≤ 500: 35.05
log P ≤ 5 (Crippen): 0.2
H-bond donors ≤ 5: 1
H-bond acceptors ≤ 10: 1

Passes all four rules.

Predictions, not measurements; each names its method. A measured log P, where a source reports one, is under Physical properties.

Safety

Danger

Harmonized EU classification (CLP Annex VI). Source [6].

Corrosive
Environmental hazard

H314Causes severe skin burns and eye damage
H400Very toxic to aquatic life

Precautionary statements: P260, P264, P273, P280, P301+P330+P331, P302+P361+P354, P304+P340, P305+P354+P338, P316, P321, P363, P391, P405, P501

View all classifications (3)

[6] Regulation (EC) No 1272/2008 of the European Parliament and of the Council · DangerH314, H400
[7] European Chemicals Agency (ECHA)This chemical does not meet GHS hazard criteria for < 0.1% (4 of 6275) of reports.
[7] European Chemicals Agency (ECHA) · 6,275 reports · DangerH314, H318, H335, H400

Exposure limits

TLV: 18 mg/m[3]
IDLH: 300 ppm (ammonia)[4]
MAK (Maximale Arbeitsplatz Konzentration): 14 mg/m[3]

First aid

Excerpt from ERG Guide 154 [Substances - Toxic and/or Corrosive (Non-Combustible)]: Refer to the "General First Aid" section. Specific First Aid: For corrosives, in case of contact, immediately flush skin or eyes with running water for at least 30 minutes. Additional flushing may be required. (ERG, 2024)[1]
General First Aid: · Call 911 or emergency medical service. · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination. · Move victim to fresh air if it can be done safely. · Administer oxygen if breathing is difficult. · If victim is not breathing: -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance. -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped…[8]
General First Aid: · Call 911 or emergency medical service. · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination. · Move victim to fresh air if it can be done safely. · Administer oxygen if breathing is difficult. · If victim is not breathing: -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance. -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped…[8]
General First Aid: · Call 911 or emergency medical service. · Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination. · Move victim to fresh air if it can be done safely. · Administer oxygen if breathing is difficult. · If victim is not breathing: -- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance. -- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped…[8]

Storage

Store in an area without drain or sewer access. Separated from food and feedstuffs. See Chemical Dangers. Cool. Well closed. Keep in a well-ventilated room. Provision to contain effluent from fire extinguishing.[3]

Incompatibilities

Caustic LIQ forms explosive CMPD WITH MANY heavy metals SUCH AS silver, LEAD, ZINC, & their salts, especially halide salts.[4]
With sodium hydroxide and silver nitrate: During preparation of an oxidizing agent on a larger scale than described, addition of warm sodium hydroxide solution to warm ammoniacal silver nitrate with stirring caused immediate precipitation of black silver nitride, which exploded. Similar incidents had been reported previously, including one where explosion appeared to be initiated by addition of Devarda's alloy (Al-Cu-Zn).[4]
Incompatible with acrolein, nitromethane, acrylic acid, chlorosulfonic acid, dimethyl sulfate, halogens, (Au + aqua regia), HCl, HF, HNO3, oleum, beta-propiolactone, propylene oxide, ... Ag2O, (Ag2O + C2H5OH), AgMnO4, H2SO4.[4]

Safety data sheets on the supplier’s page: Thermo Fisher Scientific, VladaChem, MuseChem.

Always read the supplier’s safety data sheet before working with it.

Literature

Reading PubChem, OpenAlex and GSRS…

Bioactivity

Reading ChEMBL…

References

[1]CAMEO Chemicals · Public domain (NOAA) · via PubChem · retrieved 2026-10-14
[2]EPA Chemical Data Reporting (CDR) · Public domain (US EPA) · via PubChem · retrieved 2026-10-14
[3]ILO-WHO International Chemical Safety Cards (ICSCs) · CC BY 4.0 · via PubChem · retrieved 2026-10-14
[4]Hazardous Substances Data Bank (HSDB) · Public domain (US NLM) · via PubChem · retrieved 2026-10-14
[5]PAC Chemical Database, U.S. Department of Energy · Public domain (US DOE) · via PubChem · retrieved 2026-10-14
[6]Regulation (EC) No 1272/2008 of the European Parliament and of the Council · EU reuse policy, CC BY 4.0 · via PubChem · retrieved 2026-10-14
[7]European Chemicals Agency (ECHA) · ECHA legal notice: reuse with acknowledgement · via PubChem · retrieved 2026-10-14
[8]Emergency Response Guidebook (ERG) · Public domain (US DOT) · via PubChem · retrieved 2026-10-14
·Calculated values: computed by Athanor with RDKit 2026.09 from the structure.
·Literature on PubChem

Data last updated 2026-10-14.