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Physical & Chemical properties

Melting point / freezing point

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Reference
Endpoint:
melting point/freezing point
Type of information:
experimental study
Adequacy of study:
key study
Study period:
From 20 September 2013 (date of the measurement) to 06 November 2013 (date of the test report)
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
GLP compliance:
no
Other quality assurance:
other: laboratory certified according to ISO/TS 16949
Type of method:
thermal analysis
Key result
Melting / freezing pt.:
> 600 °C
Decomposition:
yes
Decomp. temp.:
> 600 °C

No precise melting point was determined. The substance decomposes at temperatures above 600°C, with a significant weight loss related to an endothermic peak at 610°C, followed by a roughly constant decrease of the head flow rate.

The measurement shows a slight endothermic behavior in the temperature range from approximately 30°C to approximately 400 °C related with a moderate weight loss of around 2.1%. This is most likely due to loss of water coming from the physically adsorbed humidity and the decomposition of possible impurities (crystallisation water, hydrates).

At 428°C and 473°C (Peak Onset) two endothermic enthalpy peaks are measured. Due to the thermal flow behavior it is considered that these peaks relate to a solid-solid phase transition of the crystal structure.

At a temperature above 600°C a significant weight loss is seen in conjunction with an endothermic enthalpy peak at 602°C (Onset peak) followed by a roughly constant decrease of the heat flow rate. It is assumed that Li3AlF6 will melt under decomposition at temperatures above 600°C.

Conclusions:
It is assumed that Li3AlF6 will melt under decomposition at temperatures above 600°C.
Executive summary:

In this study the melting point of Lithium cryolite has been measured by a Differential Thermal Analysis (DTA) combined with a Thermal Gravimetry (TG) in accordance with the OECD Testing Guideline 102.

No precise melting point was determined. The substance decomposes at temperatures above 600°C, with a significant weight loss related to an endothermic peak at 610°C, followed by a roughly constant decrease of the head flow rate.

It is assumed that Li3AlF6 will melt under decomposition at temperatures above 600°C.

Description of key information

Li3AlF6 melts under decomposition at temperatures above 600°C.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
600 °C

Additional information

One reliable key study is available for this endpoint. In this study the melting point of Lithium cryolite has been measured by a Differential Thermal Analysis (DTA) combined with a Thermal Gravimetry (TG) in accordance with the OECD Testing Guideline 102.

No precise melting point was determined. The substance decomposes at temperatures above 600°C, with a significant weight loss related to an endothermic peak at 610°C, followed by a roughly constant decrease of the head flow rate.