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EC number: 241-034-8 | CAS number: 16961-83-4
Melting point / freezing point
Administrative data
Link to relevant study record(s)
- Endpoint:
- melting point/freezing point
- Type of information:
- experimental study
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Secondary source cited in US ATSDR review
- Qualifier:
- according to guideline
- Guideline:
- other: not reported
- Principles of method if other than guideline:
- No methodological details are reported
- GLP compliance:
- no
- Type of method:
- other: no details
- Melting / freezing pt.:
- -15.5 °C
- Remarks on result:
- other: 25% solution
- Conclusions:
- The freezing point of a 25% solution of hexafluorosilicic acid is reported to be -15.5 degrees Celsius.
- Executive summary:
The freezing point of a 25% solution of hexafluorosilicic acid is reported to be -15.5 degrees Celsius.
- Endpoint:
- melting point/freezing point
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- other: Modern, proprietary study
- Qualifier:
- no guideline followed
- Principles of method if other than guideline:
- The freezing point of the substance was determined by differential scanning calorimetry (DSC).
- GLP compliance:
- no
- Type of method:
- other: Differential scanning calorimetry (DSC).
- Melting / freezing pt.:
- -16.6 °C
- Decomposition:
- no
- Conclusions:
- The freezing point of the sample was -16.6°C.
- Executive summary:
The freezing point of a sample of 10% aqueous hexafluorosilicic acid was found to be -16.6°C using differential scanning calorimetry (DSC).
Referenceopen allclose all
The freezing point of a 25% solution of hexafluorosilicic acid is reported to be -15.5 degrees Celsius.
Melting began at around -20 °C but the broad nature of the peak produced an extrapolated onset temperature of -8.6 °C with a peak temperature of 0.5 °C. The controlled cooling of the sample showed the sample to solidify sharply at -16.6 °C and was completely solid by -24 °C. The subsequent second heating of the sample produced a similar broad peak to that seen in the first heat with an extrapolated onset temperature of -6.6 °C and a peak temperature of 0.1 °C.
Description of key information
Freezing point of a sample of 10% aqueous hexafluorosilicic acid: -16.6°C
Key value for chemical safety assessment
- Melting / freezing point at 101 325 Pa:
- -16.6 °C
Additional information
The freezing point of a sample of 10% aqueous hexafluorosilicic acid was found to be -16.6°C using differential scanning calorimetry (DSC).The freezing point of a 25% solution of hexafluorosilicic acid is reported to be -15.5 °C. The freezing point of a 60 -70% aqueous solution of hexafluorosilicic acid is reported to be 19 °C.
Since concentrations above about 30 -35% are not stable, the results from the 10% and 25% solutions are more relevant and will be used for the assessment of the registered substance. The Melting point of the 10% solution was determined using the most sophisticated test design and hence the result from this test will be used as key informaiton, i.e., the melting point is -16.6°C.
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