Magnesium hydrogenorthophosphate

Melting point / freezing point

Link to relevant study record(s)

Reference

Endpoint:

melting point/freezing point

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

Testing was conducted between 30 September 2009 and 17 November 2009.

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

This study is conducted according to an appropriate method and under the conditions of GLP and therefore the study is considered to be acceptable and to adequately satisfy the regulatory requirement as a key study for this endpoint. The rationale for reliability has not been amended despite the use as read across data. This approach is justified on the basis that although the test material is a hydrated form of the substance to be registered, the relevant study observations / measurements have been made with a view to determining the properties on the anhydrous magnesium hydrogenorthophosphate.

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

Date of GLP inspection: 15 September 2009 Date of Signature on GLP certificate: 26 November 2009

Type of method:

thermal analysis

Remarks:

Differential scanning calorimetry (DSC)

Melting / freezing pt.:

> 723 K

Remarks on result:

other: .

SEE ATTACHMENT FOR THERMOGRAMS.

Screening test result:

A single significant endotherm event to investigate at approximately 185°C. The section of thermogram in brackets (approximately 20 to 40°C) indicates an invalid data region where the instrument response had not yet stabilised and originates from the specific heat capacity of the sample.

Definitive test result:

Thermographic Data – Determination 1 – Heating Step 1

Thermal Event	Interpretation	Temperature
		ºC	K
Endotherm onset temperature	Onset of dehydration of the sample	141.81	415

Thermographic Data – Determination 2 – Heating Step 1

Thermal Event	Interpretation	Temperature
		ºC	K
Endotherm onset temperature	Onset of dehydration of the sample	145.05	418

Overall result: Melting temperature greater than 450°C (>723 K). The test material underwent dehydration from approximately 415 K, but this thermal event was not associated with a phase transition (i.e. melting) of the test material.

Conclusions:

The test material was determined to have a melting temperature greater than 450°C (723 K). The test material was also identified as undergoing dehydration from approximately 415 K but this thermal event was not associated with a phase transition (i.e. melting) of the test material.

Description of key information

Melting point: > 450 °C (EU Method A.1, OECD 102, GLP)

Key value for chemical safety assessment

Melting / freezing point at 101 325 Pa:

450 °C

Additional information

The test material was determined to have a melting temperature greater than 723 K (450°C).