Lanthanum trihydroxide

Melting point / freezing point

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

06 February 2014 - 26 February 2014

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

thermal analysis

Melting / freezing pt.:

> 400 °C

Remarks on result:

other: No melting point was determined up to 400 °C, then maximum temperature of the crucibles during determinations 1 and 2.

On heating the test material up to a temperature of 400 °C (determination 1 and 2) the absence of any significant thermal events and an unchanged final test material residue on completion of each determination confirmed the absence of any phase transitions i.e. melting, for the test material. Minor, but variable endotherm was observed during these determinations; however on investigation at a reduced heating rate, these were not replicated in determinations 3 and 4. As these events had been confirmed not to be attributable to melting, potentially they originated from the loss of moisture or an alternative volatile impurity. Information provided by the sponsor indicated a loss on drying content of 0.96% for the test material. An example thermogram from determination 1 is attached below.

The test material did not melt at a temperature below 400 °C (673 K).

Conclusions:

Under the conditions of the test, no significant thermal event was observed and the test material residue remained unchanged after heating to 400 °C. Therefore it was determined that the melting point of the test material was > 400 °C (673 K).

Executive summary:

The melting point of the test material was determined in a GLP study performed in accordance with EU Test Method A.1 and OECD guideline 102, using the differential scanning calorimetry method.

Aliquots of test material were placed in aluminium crucibles. The crucibles for determinations 1 and 2 were heated up from 25 to 400 °C at a rate of 20 °C/min, the crucibles for determinations 3 and 4 were heated up from 165 to 215 °C at a rate of 1 °C/min. The appearance of the samples was determined before and after the test.

On heating the test material up to a temperature of 400 °C (determination 1 and 2) the absence of any significant thermal events and an unchanged final test material residue on completion of each determination confirmed the absence of any phase transitions i.e. melting, for the test material. Minor, but variable endotherm was observed during these determinations; however on investigation at a reduced heating rate, these were not replicated in determinations 3 and 4. As these events had been confirmed not to be attributable to melting, potentially they originated from the loss of moisture or an alternative volatile impurity. Information provided by the sponsor indicated a loss on drying content of 0.96% for the test material.

Under the conditions of the test it was determined that there was no melting point below 400 °C (673 K).

Reference 2

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

supporting study

Study period:

not reported

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Valid with restrictions. This is peer reviewed data where the test methodology and identity of the substance have been evaluated, and a reliable and representative value for the endpoint has been selected. No information on GLP status or test guideline followed is available.

Qualifier:

no guideline available

Principles of method if other than guideline:

Handbook data does not specify the method. Data from peer reviewed source.

GLP compliance:

not specified

Type of method:

other: Handbook data does not specify the method. Data from peer reviewed source.

Decomposition:

yes

No temperature is quoted for the decomposition of the test material.

Conclusions:

The test material decomposed. No temperature was quoted for the decomposition.

Executive summary:

Information about the melting point of the test substance was taken from a peer reviewed handbook. The test material decomposed. No temperature was quoted for the decomposition.

Description of key information

The test material does not melt below 400 °C (673 K).

Additional information

The key study was performed under GLP conditions and conducted in accordance with EU Test Method A.1 and OECD guideline 102, using the differential scanning calorimetry method. The study was assigned a reliability score of 1 in accordance with the criteria set forth by Klimisch (1997).

On heating the test material up to a temperature of 400 °C (determination 1 and 2) the absence of any significant thermal events and an unchanged final test material residue on completion of each determination confirmed the absence of any phase transitions i.e. melting, for the test material. Minor, but variable endotherm was observed during these determinations; however on investigation at a reduced heating rate, these were not replicated in determinations 3 and 4. As these events had been confirmed not to be attributable to melting, potentially they originated from the loss of moisture or an alternative volatile impurity. Information provided by the sponsor indicated a loss on drying content of 0.96% for the test material.

Under the conditions of the test it was determined that there was no melting point below 400 °C (673 K).

 

Data from a peer-reviewed handbook has been provided as supporting information. This data was assigned a reliability score of 2 in accordance with the criteria set forth by Klimisch (1997).

Lide, D.R., et al. (2009): The handbook reports that the test material decomposed (no temperature was quoted for the decomposition).