Dysprosium 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:

From 17 September 2014 to 12 February 2015

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:

>= 1 370 - < 1 430 g/L

Conc. based on:

test mat.

Temp.:

20.4 °C

pH:

>= -0.08 - <= -0.03

Remarks on result:

other: The test item was completely dissolved at 1370 g/L (pH = -0.03, 20.6°C), while precipitation was observed at 1430 g/L (pH = -0.08, 20.1°C). The temperature reported above is the mean between 20.1 and 20.6 °C.

Water solubility:

711 g/L

Conc. based on:

test mat.

Temp.:

19.3 °C

pH:

5.08

Remarks on result:

other: The test item partially precipitated and some part of the substance was dissolved at pH = 5.08.

Temp.:

21.2 °C

pH:

7.2

Remarks on result:

other: A significant impact of pH (at pH = 7.20) was observed on solubility. The added test item was considered entirely precipitated. No maximum solubility could be determined.

Details on results:

Due to the high solubility observed during the assay without pH adjustment (pH close to 0), no definitive test was conducted. The experiments intended to investigate the pH effect were stopped after reaching the pH of 7 where the test item was entirely precipitated.

After a preliminary assay, the maximum solubility of dysprosium trinitrate in demineralised water was determined to be between 1370 and 1430 g/L at 20.1 - 20.6°C. The pH of the solution was between -0.08 to -0.03.

The influence of pH increase was then investigated by adding sodium hydroxide to a solution of dysprosium trinitrate of ca. 1370 g/L. After adjustment to pH = 5.08, dysprosium trinitrate was partially dissolved at a concentration of 711 g/L, taking the volume of sodium hydroxide added into account.

The influence of pH increase was further investigated by adding sodium hydroxide to reach a pH = 7.20. At this pH, the test item was not dissolved, it was considered entirely precipitated. Therefore, it can be concluded that increasing the pH lowers the water solubility. No maximum solubility could be determined at pH 7 and it was needless to perform a subsequent assay at pH 9.

Conclusions:

The substance is concluded to be very soluble in water with a maximum solubility between 1370 and 1430 g/L (pH between -0.08 to -0.03) at 20.1 to 20.6°C. The maximum solubility significantly decreased (i.e. 711 g/L) when pH was increased to approximately 5 through addition of sodium hydroxide. At higher pH values (from at least pH =7.20), the test item was considered as entirely precipitated.

Executive summary:

The water solubility of dysprosium trinitrate was investigated in compliance with GLP and according to the preliminary test as specified in EU A.6 method and OECD test guideline 105. The influence of pH variations was also investigated. Dysprosium trinitrate was determined to be very soluble in water with a maximum solubility in the range of 1370 to 1430 g/L, at 20.1 to 20.6°C and pH = ca. 0 (between -0.08 and -0.03). The maximum solubility significantly decreased (i.e. 711 g/L) when pH was increased to approximately 5. At higher pH values (from at least 7.20), the test item was considered as entirely precipitated.

Description of key information

Dysprosium trinitrate was determined to be very soluble in water with a maximum solubility between 1370 g/L and 1430 g/L at 20.1 to 20.6°C and pH = ca. 0 (-0.08 to -0.03). It is important to note that the solubility was significantly decreased (i.e. 711 g/L) when the pH was adjusted to ca. 5. At higher pH values (i.e. from at least 7.20), dysprosium trinitrate was observed to be entirely precipitated.

Key value for chemical safety assessment

Water solubility:

1 370 g/L

at the temperature of:

20.6 °C

Additional information

An experimental study of reliability 1 according to Klimisch, performed in compliance with GLP and according to the preliminary test as specified in EU method A.6 and OECD Guideline 105, was selected as a key study.

Dysprosium trinitrate was determined to be very soluble in water with a maximum solubility in the range of 1370 to 1430 g/L, at 20.1 to 20.6°C and pH = ca. 0 (between -0.08 and -0.03). The maximum solubility significantly decreased (i.e. 711 g/L) when pH was increased to approximately 5. At higher pH values (from at least 7.20), the test item was considered as entirely precipitated.