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Please be aware that this old REACH registration data factsheet is no longer maintained; it remains frozen as of 19th May 2023.

The new ECHA CHEM database has been released by ECHA, and it now contains all REACH registration data. There are more details on the transition of ECHA's published data to ECHA CHEM here.

Diss Factsheets

Physical & Chemical properties

Endpoint summary

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Administrative data

Description of key information

Additional information

Ammonia, anhydrous is a colourless gas.

The table below summarises the chemical and physical properties of ammonia, anhydrous.



Substance type

Inorganic compound

Appearance/physical state/colour

Colourless gas

Melting point

–78 C

Boiling point

–33 C

at 20°C

0.708 kg/m³

Particle size distribution

Study not required as the substance is marketed or used in a non-solid or granular form.

Vapour pressure
at 20°C

8611 hPa

Partition Coefficient

Not required as test substance is inorganic. A

log Kow: 0.23 has been calculated.

Water solubility at 20C

482 g/L

Surface Tension at 25C

Not required.

Flash point

The substance is inorganic so therefore the flash point does not need to be measured.

Auto flammability

651 °C




There are no chemical groups associated with explosive properties.

Oxidising properties

No oxidising properties. The test substance does not contain any oxygen or halogen atoms

Stability in organic solvents and identity of relevant degradation products

The study does not need to be conducted if the substance is inorganic.

Dissociation constant at 25 °C

pKa = 9.25


The data requirement can be waived as the substance is a gas at room temperature and atmospheric pressure. However the viscosity of anhydrous ammonia was measured to 0.475, 0.317, 0.276 & 0.255 centipoises at -69, -50, -40 & -33.5  ⁰C respectively.

The viscosity of aqueous ammonia (26%) is temperature-dependent and is reported to be between 0.7 -5 centipoise (mPa.s) at temperatures of between -40 and 48.9 degrees Celsius. The viscosity at 26.7 degrees Celsius is reported to be 1.1 centipoise (mPa.s).