Registration Dossier
Registration Dossier
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EC number: 235-185-9 | CAS number: 12125-01-8
Melting point / freezing point
Administrative data
Link to relevant study record(s)
Description of key information
Ammonium fluoride decomposes at circa 100°C before reaching its melting point according to the following reaction: 2 NH4F --> NH4HF2 + NH3
To enable the chemical safety assessment to be performed, the melting point was estimated using EPI Suite v4.10 (MPBPVP v1.43). The estimated value was 268.22°C.
Key value for chemical safety assessment
- Melting / freezing point at 101 325 Pa:
- 268.22 °C
Additional information
The Gmelin handbook of inorganic chemistry (1924) states that the decomposition temperature for ammonium fluoride, circa 100°C, is reached before the substance reaches its melting point (decomposition temperature is assumed to be reported at one atmosphere).
The CRC Handbook of Chemistry and Physics, 65th edition, B-71 (1984) stated that NH4F sublimates. Indeed, the review article by Rakov and Mel'nichenko (1984) showed that ammonium fluoride decomposes as a result of heating according to the following equation: 2 NH4F (crystalline) --> NH4HF2 (crystalline) + NH3 (gas).
However, according to the CRC Handbook of Chemistry and Physics, 91st edition (2010 -2011) the melting point of ammonium fluoride was 238°C. This value is in agreement with our estimated value of 268.22°C. This latter estimation, performed using EPI Suite v4.10 (MPBPVP v1.43), enabled execution of the chemical safety assessment for the ammonium fluoride dossier.
Considering the origin of the value in the CRC Handbook of Chemistry and Physics, 91stedition (2010 -2011) was not clearly cited and the decomposition is a well known fact supported by literature, it may be the result of an estimation method instead of experimental data.
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