Niobium hydride

Melting point / freezing point

Link to relevant study record(s)

Reference

Endpoint:

melting point/freezing point

Type of information:

experimental study

Adequacy of study:

key study

Study period:

01 October 2018 to 10 January 2019

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 102 (Melting point / Melting Range)

Version / remarks:

1995

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method A.1 (Melting / Freezing Temperature)

Version / remarks:

2016

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 830.7200 (Melting Point / Melting Range)

Version / remarks:

1998

Deviations:

no

GLP compliance:

yes

Type of method:

differential scanning calorimetry

Key result

Melting / freezing pt.:

> 400 °C

Decomposition:

no

Remarks on result:

other: the substance did not melt up to 400°C. Atmospheric pressure not recorded.

Preliminary Test

No significant weight loss was observed. After the experiment, a black residue remained in the sample container (original colour: Grey). The change of the colour indicated reaction and/or decomposition of the test material.

 

Main Study

An endothermic effect was observed between 75 °C and 150 °C. The reason for the endothermic effect is unknown. After the experiment, the residue in the sample container was unchanged.

In order to investigate the endothermic effect, Experiment 2 was stopped directly after the effect. After the experiment, the residue in the sample container was unchanged.

To investigate the endothermic effect, a repeated heating cycle was applied in the Experiment 3. During cooling, an exothermic effect between 100 °C and 120 °C was found. The reason for the effect was unknown. With the second heating, similar results as with the first heating were obtained (i.e. endothermic effect between 100 and 140 °C). The effects were probably obtained by a change of crystal structure. After the experiment, the residue in the sample container was unchanged.

Conclusions:

Under the conditions of the study no melting point was observed up to 400 °C (673K). Between 100 °C and 140 °C, an endothermic peak was observed. The effect was probably due to a change of crystal structure.

Executive summary:

The melting point of the test material was assessed according to OECD Test Guideline 102, EU Method A.1, and EPA OPPTS 830.7200, under GLP conditions, using differential scanning calorimetry (DSC).

In the preliminary study no significant weight loss was observed. After the experiment, a black residue remained in the sample container (original colour: grey). The change of the colour indicated reaction and/or decomposition of the test material.

 In the main study an endothermic effect was observed between 75 °C and 150 °C. The reason for the endothermic effect is unknown. After the experiment, the residue in the sample container was unchanged.

In order to investigate the endothermic effect, Experiment 2 was stopped directly after the effect. After the experiment, the residue in the sample container was unchanged.

To investigate the endothermic effect, a repeated heating cycle was applied in the Experiment 3. During cooling, an exothermic effect between 100 °C and 120 °C was found. The reason for the effect was unknown. With the second heating, similar results as with the first heating were obtained (i.e. endothermic effect between 100 and 140 °C). The effects were probably obtained by a change of crystal structure. After the experiment, the residue in the sample container was unchanged.

Under the conditions of the study no melting point was observed up to 400 °C (673K).  Between 100 °C and 140 °C, an endothermic peak was observed.  The effect was probably due to a change of crystal structure.

Description of key information

Under the conditions of the study no melting point was observed up to 400 °C (673K).  Between 100 °C and 140 °C, an endothermic peak was observed.  The effect was probably due to a change of crystal structure.

Additional information

The melting point of the test material was assessed according to OECD Test Guideline 102, EU Method A.1, and EPA OPPTS 830.7200, under GLP conditions, using differential scanning calorimetry (DSC). The study was awarded a reliability score of 1 in accordance with the criteria set forth by Klimisch et al. (1997).

In the preliminary study no significant weight loss was observed. After the experiment, a black residue remained in the sample container (original colour: grey). The change of the colour indicated reaction and/or decomposition of the test material.

 In the main study an endothermic effect was observed between 75 °C and 150 °C. The reason for the endothermic effect is unknown. After the experiment, the residue in the sample container was unchanged.

In order to investigate the endothermic effect, Experiment 2 was stopped directly after the effect. After the experiment, the residue in the sample container was unchanged.

To investigate the endothermic effect, a repeated heating cycle was applied in the Experiment 3. During cooling, an exothermic effect between 100 °C and 120 °C was found. The reason for the effect was unknown. With the second heating, similar results as with the first heating were obtained (i.e. endothermic effect between 100 and 140 °C). The effects were probably obtained by a change of crystal structure. After the experiment, the residue in the sample container was unchanged.

Under the conditions of the study no melting point was observed up to 400 °C (673K).  Between 100 °C and 140 °C, an endothermic peak was observed.  The effect was probably due to a change of crystal structure.