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Diss Factsheets

Physical & Chemical properties

Melting point / freezing point

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melting point/freezing point
Type of information:
experimental study
Adequacy of study:
key study
Study period:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
according to guideline
OECD Guideline 102 (Melting point / Melting Range)
according to guideline
EU Method A.1 (Melting / Freezing Temperature)
according to guideline
other: OECD 113 (1981) Screening test for thermal stability and stability in air
GLP compliance:
yes (incl. QA statement)
signed 2009-10-29
Type of method:
differential scanning calorimetry
Melting / freezing pt.:
> 600 °C
Remarks on result:
other: The test item does not melt within the tested temperature range.

A DSC-measurement in closed glass crucibles showed no endothermic or exothermic effects up to the maximum temperature.

The measurement in an aluminium crucible with a hole showed no significant endothermic effect or exothermic effect up to the maximum temperature of 600 °C. An optical inspection after the measurement showed that the test item was unchanged (regarding both the physical form and the colour of the test item).

Potassium thiosulfate has a melting point >600 °C (study result)

Description of key information

Potassium thiosulfate has a melting point >600 °C (study result)

Key value for chemical safety assessment

Additional information

For the evaluation of this endpoint data from an experimental study were used as key information. The study was conducted according to GLP and according to OECD guidelines 113 (screening for thermal stability) and 102 (determination of meting point). The test data are considered as reliable without restrictions.

The thermal stability and the determination of the melting point were carried out by DSC analysis. The test item and the standard material (aluminium oxide) were heated up from ambient temperature to the final temperature (450 °C and 600 °C, respectively) at a constant heating rate under nitrogen. Closed class crucibles were used as containers for the screening test and aluminium crucibles with a small hole were used in the main test. The quantity of heat absorbed or released was measured and recorded.

Results indicate that potassium thiosulfate has a melting point > 600 °C.