Digadolinium trioxide

Density

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

relative density

Type of information:

experimental study

Adequacy of study:

key study

Study period:

07 June 2016 - 12 July 2016

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

EU Method A.3 (Relative Density)

Deviations:

yes

Remarks:

The purging time was less than 20 minutes for the first and second assays. Therefore, the first runs were not taken into account. This deviation was not considered to have affected the quality of the results obtained.

Qualifier:

according to guideline

Guideline:

OECD Guideline 109 (Density of Liquids and Solids)

Deviations:

yes

Remarks:

The purging time was less than 20 minutes for the first and second assays. Therefore, the first runs were not taken into account. This deviation was not considered to have affected the quality of the results obtained.

GLP compliance:

yes (incl. QA statement)

Type of method:

pycnometer method

Key result

Type:

relative density

Density:

ca. 7.983

Temp.:

19.9 °C

Remarks on result:

other: Mean value of two assays (assay No.1: 8.094, assay No.2: 7.871)

Two independent measurements at 20.2°C (assay No. 1) and 19.6°C (assay No. 2) were done. Runs 1, 2 and 3 of assay No. 1 and runs 1, 2, 3 and 4 of assay No. 2 were not taken into account because they did not comply with the quality criterion. A longer stabilisation time of the pressure was needed to obtain three consequent runs complying with the quality criterion.

The two assays resulted in relative densities of 8.094 ± 0.003 and 7.871 ± 0.001, respectively. The mean relative density was thus 7.983 ± 0.123 at 19.9°C.

Reference volume (Va) was 79.250 cm3.

Volume of sample cell holder (Vc) was 27.636 cm3.

Test item sample weight was 8.1766 g and 8.3251 g in assay No. 1 and 2, respectively.

The measurements are described in the table in the next section.

Conclusions:

The relative density of gadolinium oxide was determined according to EU A.3 method and OECD test guideline 109 in compliance with GLP using a gas comparison pycnometer. The relative density of the test item was determined to be 7.983 ± 0.123 at 19.9°C. The deviation from the guideline which was observed during the study is not considered to have affected the outcome of the study, since the affected runs were not taken into account for determination of the final result. Consequently, the results of the study are considered reliable without restrictions (Klimisch 1).

Reference 2

Endpoint:

density, other

Remarks:

density

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Principles of method if other than guideline:

Data obtained from the peer reviewed CRC Handbook of Chemistry and Physics. No information given on methodology.

GLP compliance:

no

Type of method:

other: no data

Type:

density

Density:

7.41 g/cm³

Conclusions:

According to the peer reviewed CRC Handbook of Chemistry and Physics, gadolinium oxide has a density of 7.41 g/cm3.

Description of key information

The relative density of gadolinium oxide was determined in a GLP study (Klimisch 1, Demangel, 2016) according to the EU A.3 method and OECD test guideline 109 using a gas comparison pycnometer. The relative density of the test item was determined to be 7.983 ± 0.123 at 19.9°C. This value is considered as the key value for gadolinium oxide.

Key value for chemical safety assessment

Relative density at 20C:

7.983

Additional information

In the key study of Demangel (2016) performed according to the EU A.3 method and OECD test guideline 109, a deviation from the guideline was observed during the study. However, since the affected runs were not taken into account for determination of the final result, the deviation is not considered to have affected the quality or the interpretation of the results obtained, hence, the results of the study are considered reliable without restrictions (Klimisch 1).

In the CRC Handbook of Chemistry and Physics (97th edition, 2016-2017) a density of 7.41 g/cm3 is reported for gadolinium oxide. The difference in the composition of the impurity content of the test items used in the key study and the study from which the handbook value was taken, would most likely explain the small but acceptable difference in the relative densities obtained in both studies. In the presence of a fully documented study, handbook data are recommended to be considered as supporting information.