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Diss Factsheets

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 10 March 2017 (date of the measurement) to 18 August 2017 (date of the test report)
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: This study does not follow the GLP requirements but has been performed according to the OECD Testing Guideline 102
Qualifier:
according to guideline
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.:
> 569 °C
Decomp. temp.:
°C

The DSC/TGA shows three endothermic peaks. The first at 119°C is connected to a weight loss of 3,7 %; it relates to a release of water and a respective transition of K2AlF5*H2O to its anhydrous form. A second peak at 521°C is observed most probably reflecting a disproportionation of the dipotassium pentafluoroaluminate into KAlF4 and K3AlF6. A third peak at 569°C represents the melting of the sample.

Conclusions:
The melting point of potassium cryolite is 569°C
Executive summary:

In this study the melting point of potassium cryolite has been measured by a Differential Thermal Analysis (DTA) combined with a Thermal Gravimetry (TG) in accordance with the OECD Testing Guideline 102. The DSC/TGA shows three endothermic peaks. The first at 119°C is connected to a weight loss of 3,7 %; it relates to a release of water and a respective transition of K2AlF5*H2O to its anhydrous form. A second peak at 521°C is observed most probably reflecting a disproportionation of the dipotassium pentafluoroaluminate into KAlF4 and K3AlF6. A third peak at 569°C represents the melting of the sample.

Description of key information

Potassium cryolite will melt at a temperature 569°C.

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:
569 °C

Additional information

One reliable key study is available for this endpoint. In this study the melting point of potassium cryolite has been measured by a Differential Thermal Analysis (DTA) combined with a Thermal Gravimetry (TG) in accordance with the OECD Testing Guideline 102. The substance will melt at a temperature of 569°C.