Barium zirconium trioxide

Water solubility

Link to relevant study record(s)

Reference

Endpoint:

water solubility

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.6 (Water Solubility)

Version / remarks:

This Test Method is equivalent to OECD Test Guideline (TG) 105 (1995).

Deviations:

no

Principles of method if other than guideline:

The test substance was dispersed / dissolved in water at a temperature of 30 deg C. The vessels were tightly stoppered and then agitated at 30 deg C. (A shaking or stirring device capable of operating at constant temperature was used). After one day, one of the vessels is removed and re-equilibrated for 24 hours at the test temperature with occasional shaking. The contents of the vessel were then centrifuged at the test temperature, and the concentration of test substance in the clear aqueous phase is determined by a suitable analytical method, in this case ICP. This was repeated on days two and three and the average value reported.

GLP compliance:

no

Type of method:

flask method

Key result

Water solubility:

1.69 mg/L

Conc. based on:

element (dissolved fraction)

Remarks:

result is for Ba ion

Temp.:

20 °C

pH:

8.4

Remarks on result:

other:

Remarks:

This analysis is for Bx 17/1791 on an as received basis

Key result

Water solubility:

8.08 mg/L

Conc. based on:

element (dissolved fraction)

Remarks:

result is for Ba2+ ion

Temp.:

20 °C

pH:

8.4

Remarks on result:

other:

Remarks:

This analysis is for Bx 18/1868

Details on results:

The soluble Zr in solution was determined in both tests to be <10 ppm. Any dissolved zirconate would be identified by ICP, so this would imply that the solubility of barium zirconate is 'insoluble'. The soluble barium ion concentration detected by ICP is most likely to have been due to the presence of soluble barium carbonate impurity - see discussion.
The variance between the two results is likely to be due to differing levels of barium carbonate impurity in the batches tested.

Conclusions:

The solubility of barium zirconate is very low. The level of soluble zirconium (as Zr) from the zirconate ion (ZrO3) was determined to be < 10 ppm in solution, which would imply that the solubility of the barium zirconate ion was also essentially insoluble. But this material has a trace level impurity of barium carbonate, which is variable dependent on the batch, and can be present at levels between 0 - 3% by weight.
Barium carbonate solubility is interpreted as slightly soluble (0.1-100 mg/L) according to the ECHA barium carbonate disemminated dossier.
The dissolved barium content in water determined for this substance is in the range 1 - 10 mg/l and is most likely due to the barium carbonate impurity, but this impurity is an integral part of the substance and hence barium zirconate must be classed as slightly soluble at an average value of 4.9 mg/l

Description of key information

The solubility of barium zirconate is very low. The level of soluble zirconium (as Zr) from the zirconate ion (ZrO3) was determined to be < 10 ppm in solution, which would imply that the solubility of the barium zirconate ion was also essentially insoluble. But this material has a trace level impurity of barium carbonate, which is variable dependent on the batch, and can be present at levels between 0 - 3% by weight.

Barium carbonate solubility is interpreted as slightly soluble (0.1-100 mg/L) according to the ECHA barium carbonate disemminated dossier.

The dissolved barium content in water determined for this substance is in the range 1 - 10 mg/l and is most likely due to the barium carbonate impurity, but this impurity is an integral part of the substance and hence barium zirconate must be classed as slightly soluble at an average value of 4.9 mg/l

Key value for chemical safety assessment

Water solubility:

4.9 mg/L

at the temperature of:

20 °C