Tricobalt tetraoxide

Flammability

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

substances / mixtures which in contact with water emit flammable gases

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance is known to be soluble in water to form a stable mixture

Reference 2

Endpoint:

flammable solids

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Reference 3

Endpoint:

pyrophoric solids

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

the study does not need to be conducted because the substance is known to be stable in contact with air at room temperature for prolonged periods of time (days) and hence, the classification procedure does not need to be applied

Description of key information

Testing of flammability does not appear scientifically necessary:

- Testing of flammability of solids (A.10) and gases (A.11) is not considered to be required, since a flammability test with cobalt stearate (oxidation state +2) did not show flammable properties, since tricobalt tetraoxide represents an inorganic salt containing cobalt in the oxidised status (2+) and an anion of an acid which is less susceptible to any form of oxidation than stearic acid, it is less combustible than cobalt stearat.

- Testing for flammability in contact with water (A.12) is not considered to be required, because tricobalt tetraoxide does not contain groups that might lead to a reaction with water or damp air, leading to the development of dangerous amounts of gas or gases which may be highly flammable.

- Testing of pyrophoric properties of solids and liquids (A.13) is not considered to be required, since tricobalt tetraoxide is stable at ambient temperature. It does not contain any chemical group that might lead to spontaneous ignition a short time after coming in contact with air at room temperature (approx. 20 °C).

Key value for chemical safety assessment

Flammability:

not classified

Additional information

Flammability (solids)

The study does not need to be conducted. Testing of flammability is not considered to be required for inorganic oxides in which the cation is in its highest possible oxidation state (i.e. Co(3+)), and which therefore are incapable of further reaction with oxygen. This substance can thus be designated as non-flammable. (Guidance on information requirements and chemical safety assessment Chapter R.7a: Endpoint specific guidance, section R.7.1.10.3).  Furthermore, a test on the flammability according to EC method A.10 was recently conducted for stearic acid cobalt salt with cobalt in the oxidised status (+2), yielding a result of “not flammable”. Since tricobalt tetraoxide presents an mixed inorganic oxide containing cobalt in the oxidised status (2+) and oxygen which is not susceptible to any form of further oxidation, the substance is thus intrinsically less combustible than the stearic acid cobalt salt.

Pyrophoric properties

Testing for pyrophoric properties of solids is not considered to be required, since this substance is stable at ambient temperature. This substance also does not contain any chemical groups that might lead to spontaneous ignition a short time after coming in contact with air at room temperature (circa 20 °C) . Furthermore, long-term industrial experience in handling shows that the substance does not ignite in contact with air.

Flammability in contact with water

Testing of flammability in contact with water is not considered to be required, because the substance does not contain groups that might lead to a reaction with water or damp air, leading to the development of dangerous amounts of gas or gases which may be highly flammable. Furthermore, long-term industrial experience in practical handling of the substance shows that it does not react with water, and recent experimental testing for water solubility has also not reported any formation of gases.

Justification for classification or non-classification

Tricobalt tetraoxide does not need to be classified according to CLP Regulation (EC) No 1272/2008 since it is not highly flammable.