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Physical & Chemical properties

Density

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Endpoint:
density
Remarks:
density
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: Non-guideline study. Very limited experimental detail. Purity of the sample not addressed.
Reason / purpose:
reference to same study
Qualifier:
no guideline followed
Principles of method if other than guideline:
Liquid pycnometer, using kerosene as the working liquid.
GLP compliance:
no
Type of method:
pycnometer method
Type:
density
Density:
1.33 g/cm³
Temp.:
25 °C
Remarks on result:
other: ±0.04
Conclusions:
The results are not considered reliable, though the values are considered to be plausible. Uncertainty in the result was quantified.
Endpoint:
density
Remarks:
density
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: Non-guideline study. Very limited experimental detail. Source and purity of the sample addressed.
Qualifier:
no guideline followed
Principles of method if other than guideline:
No data.
GLP compliance:
no
Type of method:
air comparison pycnometer (for solids)
Type:
density
Density:
1.37 g/cm³
Temp.:
23 °C
Conclusions:
The results are not considered reliable, though the values are considered to be plausible.
Endpoint:
density
Remarks:
density
Type of information:
experimental study
Adequacy of study:
weight of evidence
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: see 'Remark'
Remarks:
Non-standard method. The density derived from crystallographic measurements will represent the ideal case of a single crystal. The crystal structure was successfully solved with a good quality data set (final R=5.6%). The structure does not require special consideration (e.g. contains solvent; very dense or very open structure; large number of subunits in the assymetric unit cell, or heterogenous subunits, such that the symmetry or packing is uncertain). Temperature only reported as "room temperature". No information on purity of the substance. In particular limited information given on the determination of the lattice constants, from which the unit-cell volume, and hence density is derived.
Qualifier:
no guideline followed
Principles of method if other than guideline:
The density is calculated from the known volume of the unit cell, the number of molecules per unit cell, and the molecular weight. The unit cell and number of molecules per unit cell are derived from the solved x-ray crystal structure.
GLP compliance:
no
Type of method:
other: x-ray crystallography
Type:
density
Density:
1.351 g/cm³
Remarks on result:
other: Room temperature; calculated from crystal structure.

a=12.901(2)Å , b=4.982(1)Å, c=20.987(3)Å, B=91.50(2)°, Z=8

Space group: I2/a, 2θ(max)=70°, measured reflections=6167, unique reflections=2970, R=5.6%, wR=4.8%

Conclusions:
Exact temperature and purity of the substance were not reported, nor were details on lattice constant determination, which are critical for the unit cell volume. The crystal structure was successfully solved with a good quality data set (final R=5.6%). The density derived from crystallographic measurements will represent the ideal case of a single crystal. The structure does not require special consideration (e.g. contains solvent; very dense or very open structure; large number of subunits in the assymetric unit cell, or heterogenous subunits, such that the symmetry or packing is uncertain).

Description of key information

1.33±4g/cm3, 25°C, pycnometery, Gloria 1963
1.351g/cm3, 25°C, crystallography, Pertlik 1990
1.37g/cm3, 23°C, air pycnometery, Lerk 1977
1.32g/cm3, flotation and pycnometery, McCrone 1953
1.308g/cm3, crystallography, McCrone 1953

Key value for chemical safety assessment

Relative density at 20C:
1.34

Additional information

Several density measurements were available from the published literature. Although none of the published densities were measured according to guidelines, there was good agreement between all reported values, using different techniques and performed by independant laboratories, on independant samples. As a result, the average of the values (n=5) was selected for risk assessment purposes. Considering the good agreement between independent results, based on the weight-of-evidence the available data is considered to be reliable and adequate for classification and labelling, and risk assessment purposes in accordance with Regulation (EC) No. 1907/2006, Annex XI, 1.2.