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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 03 Nov 2005 to 19 Apr 2006
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Reason / purpose:
reference to same study
Qualifier:
according to
Guideline:
OECD Guideline 102 (Melting point / Melting Range)
Version / remarks:
and EU method A1 (Melting / Freezing temperature)
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of method:
thermal analysis
Key result
Melting / freezing pt.:
> 400 °C
Decomposition:
no

Preliminary test: No endothermic heat effect was observed from which melting could be deduced. After the experiment, the sample was still a powder, losing about 0.6% of its mass.

Main test: No endothermic reaction could be observed. After the experiment, the sample had lost about 0.2% of its mass and the sample was unchanged in appearance.

Conclusions:
Cerium dioxide does not melt under the conditions of the test.
Executive summary:

Melting point of cerium dioxide was assessed using a thermal analysis, according to OECD Guideline 102.

A test item amount of 24.06 mg was heated up from 25°C to 400°C at a rate of 20°C/min during a preliminary test. The quantities of heat absorbed or released were measured by Differential Scanning Calorimeter and recorded. No endothermic heat effect was observed from which melting could be deduced. After the experiment, the sample was still a powder, losing about 0.6% of its mass.

The thermal analysis was repeated in a main test with 27.02 mg of test item in the same temperature range but with the rise adjusted to 10°C/min.

No endothermic reaction could be observed. After the experiment, the sample had lost about 0.2% of its mass and the sample was unchanged in appearance.

In conclusion, cerium dioxide does not melt under the conditions of the test.

Description of key information

Cerium dioxide did not melt under the conditions of the test.

Melting point > 400°C.

Key value for chemical safety assessment

Additional information

The existing data only concern the bulk form. An experimental study, scored as Klimisch 1, is selected as a key study, giving a melting point > 400°C. Two publications and one reference handbook, all selected as supporting studies, give consistent high melting point values, ranging between 2400 and 2600°C.