Neodymium trinitrate

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Study period:

22 March 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Deviations:

no

Qualifier:

according to guideline

Guideline:

OECD Guideline 105 (Water Solubility)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Type of method:

other: preliminary estimate of solubility by visual judgement with an investigation of the influence of pH variations.

Key result

Water solubility:

> 1 020 - < 1 220 g/L

Conc. based on:

test mat.

Temp.:

21 °C

pH:

3.4

Remarks on result:

other: The test item was completely dissolved at 1020 g/L while precipitation was observed at 1220 g/L

Water solubility:

1 000 g/L

Temp.:

20.5 °C

pH:

4.92

Remarks on result:

other: The test item was completely dissolved at 1000 g/L revealing no effect on solubility of a pH = ca.5

Temp.:

21.3 °C

pH:

6.98

Remarks on result:

other: A significant impact of pH=ca.7 was observed on solubility, the test item precipitating and giving a pasty solution. No maximum solubility could be determined.

Details on results:

Due to the high solubility observed during the assay without pH adjustment (i.e. pH = ca. 3.4), no definitive test was conducted. The experiments intended to investigate the pH effect were stopped after reaching the pH of 6.98 as it was not possible to reach a higher pH value due to the difficulty to homogenize the solution.

After a preliminary assay, the maximum solubility in demineralized water of neodymium trinitrate was determined to be between 1020 and 1220 g/L at 21°C. The pH of the solution was 3.4.

The influence of the pH increase was then investigated by adding sodium hydroxide to the solution of neodymium trinitrate at ca. 1020 g/L. After adjustment to pH = 4.92. Neodymium trinitrate was completely dissolved at a concentration of ca. 1000 g/L, taking the amount of sodium hydroxide added into account..

After subsequent addition of sodium hydroxide, a pH = 6.98 was obtained. The test item was not dissolved, the solution became pasty and a whitish precipitate was observed. It became difficult to homogenize the test mixture which never reached pH > 7. Although it can be concluded that increasing the pH will lower the water solubility, no maximum solubility could be determined at pH 7.

Conclusions:

Interpretation of results (migrated information): very soluble (> 10000 mg/L)
The substance is concluded to be very soluble in water with a maximum solubility in the range of 1.02 to 1.22 kg/L, at 20°C and pH 3.4. The maximum solubility did not change when increasing the pH to approx 5, while above (i.e. pH = 6.98, not possible to reach a pH > 7) the test item precipitated and the solution became pasty.

Description of key information

The substance is concluded to be very soluble in water with a maximum solubility in the range of 1.02 to 1.22 kg/L, at 20°C and pH 3.4. The maximum solubility did not change when increasing the pH to approx 5, while above (i.e. pH = 6.98, not possible to reach a pH > 7) the test item precipitated and the solution became pasty.

Key value for chemical safety assessment

Water solubility:

1 200 g/L

at the temperature of:

20 °C