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Diss Factsheets

Physical & Chemical properties

Melting point / freezing point

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Administrative data

Link to relevant study record(s)

melting point/freezing point
Type of information:
experimental study
Adequacy of study:
key study
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
data from handbook or collection of data
Principles of method if other than guideline:
Not specified
GLP compliance:
not specified
Type of method:
other: not specified
Melting / freezing pt.:
>= 39 - <= 41 °C
Atm. press.:
ca. 1 atm
Ammonium iron(III) sulfate dodecahydrate melts between 39 °C and 41 °C.
Executive summary:

According to Hawley's Condensed Chemical Dictionary (published in 2016), Ammonium iron(III) sulfate dodecahydrate melts between 39 °C and 41 °C.

Description of key information

Ammonium iron(III) sulfate dodecahydrate melts at temperatures close to room temperature. CRC Handbook of Chemistry and Physics (2005) and Handbook of Inorganic Chemicals (2003) report a value of around 37 °C. Hawley’s Condensed Chemical Dictionary, 16th Edition (2003) reports a melting point range from 39 °C to 41 °C.

In the literature no melting point of anhydrous ammonium iron(III) sulfate was found. For compounds consisting of the same ions, iron(III) sulfate and ammonium sulfate, no melting but decomposition at elevated temperatures (iron(III) sulfate: 480 °C; ammonium sulfate: > 235 °C) is described. Therefore, anhydrous ammonium iron(III) sulfate is expected to decompose as well at elevated temperatures. 

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
40 °C

Additional information