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Melting point / freezing point

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melting point/freezing point
Type of information:
experimental study
Adequacy of study:
key study
Study period:
28 May 2010- 5 August 2010
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
This study has been performed according to OECD and EC guidelines and according to GLP principles. The test substance is adequately characterised. Therefore full validation applies.
according to guideline
OECD Guideline 102 (Melting point / Melting Range)
according to guideline
EU Method A.1 (Melting / Freezing Temperature)
GLP compliance:
yes (incl. QA statement)
Type of method:
thermal analysis
ThermoGravimetric Analysis (TGA) + Differential Scanning Calorimetry (DSC)
Remarks on result:
other: No melting and/or boiling point below 400°C (673 K) could be determined using DSC.


Preliminary test

The TGA-curve of the test substance shows that from 75°C upwards the weight of the sample decreased significantly. At 281°C the sample weight had decreased by 25%.


After the experiment, a black reddish residue remained on the outside of the sample container (original colour: white). The change of the colour indicated reaction and/or decomposition of the test substance.


Main study

The DSC-curve obtained with the first experiment shows that several small endothermic effects were observed. It was assumed that elimination of the water from the molecular structure of the test substance was predominantly responsible for these endothermic effects. No endothermic effects which could be attributed to either melting and/or boiling of the test substance were observed.


After the experiment, a white residue remained in the sample container.

Decomposition of test substance, without melting up to 400°C (673 K).
Executive summary:

The melting point of dialuminium chloride pentahydroxide was investigated according to OECD/EC guidelines, thermal analysis method. A preliminary assay was conducted with TGA; one main measurement was performed with DSC under nitrogen. No melting (i.e. transition to liquid form) was observed up to 400°C, but weight loss and endotherms were recorded, and attributed to decomposition corresponding to crystal water loss.

Description of key information

Decomposes without melting up to 400°C.

Key value for chemical safety assessment

Additional information

A fully reliable experimental study, conducted according to a recognized OECD/EC method and under GLP, is available. Therefore, it is considered as a key study. Crystal water loss was observed from ca 75°C, but no melting occured up to 400°C. Therefore, the result is expressed as a limit value, and cannot be retained as key data for purpose of CSA.