Yttrium trinitrate

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

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

no guideline followed

Principles of method if other than guideline:

The solid-liquid equilibria of H2O-Y(NO3)3 systems are studied using conductimetry and controlled thermal flux analysis. The solid phase was studied using X-ray diffraction, thermogravimetry and chemical analysis such as calcination and Inductively Coupled Plasma-Atomic Emission Spectrometry.

GLP compliance:

no

Type of method:

differential scanning calorimetry

Key result

Decomposition:

yes

Decomp. temp.:

ca. 300 °C

Remarks on result:

other: The atmospheric pressure was not reported.

The metastable melting point of the tetra-, penta- and hexahydrate was determined to be 120.4, 77.8 and 51.8°C, respectively. The phase transitions could probably best be described as solubilisation of Y(NO)3 in hydration water. Further release of water results in the anhydrous form at approximately 235°C.

Above 300°C and up to 500°C further conversion to YONO3, Y4O3(NO3)3 and finally Y2O3 is observed. As a result, yttrium trinitrate did not melt over the temperature range tested.

Conclusions:

When heating Y(NO3)3 hexahydrate, phase transitions are observed at 51.8°C, 77.8°C (pentahydrate) and 120.4°C (tetrahydrate), which best can be described as solubilisation of Y(NO3)3 in its hydration water. Above 300°C and up to 500°C further conversion to YONO3, Y4O3(NO3)3 and finally Y2O3 is observed.

Description of key information

In a published study, decomposition of yttrium trinitrate was noted from a DSC scan to start from approximately 300°C (Bouchet et al., 1994). As a result, yttrium trinitrate did not melt over the temperature range tested.

Additional information

A literature study was identified which has been assigned key study status for this endpoint (Bouchet et al., 1994; Klimisch 2). In this study, when heating Y(NO3)3 hexahydrate, phase transitions were observed at 51.8°C, 77.8°C (pentahydrate) and 120.4°C (tetrahydrate), which can best be described as solubilisation of Y(NO3)3 in its hydration water. Above 300°C and up to 500°C, conversion of Y(NO3)3 to YONO3, Y4O3(NO3)3 and finally Y2O3 is observed. Yttrium trinitrate is concluded to decompose starting from approximately 300°C. Yttrium trinitrate did not melt over the temperature range tested in this study.