Zirconium dinitrate oxide

Flammability

Link to relevant study record(s)

Reference

Reference 1

Endpoint:

flammable solids

Data waiving:

other justification

Justification for data waiving:

other:

Reference 2

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 experience in production or handling shows that the substance does not react with water, e.g. the substance is manufactured with water or washed with water

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

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

Based on a theoretical assessment and on the observed endothermic reactions in the DSC analysis, zirconium dinitrate oxide is concluded to be non-flammable. Day-to-day handling of the substance shows that the substance is not flammable in contact with water or with air.

Key value for chemical safety assessment

Flammability:

non flammable

Additional information

Flammability is usually seen as the ease with which the substance can burn or be ignited. However it also includes spontaneous flammability (pyrophoricity) and ignition on contact with water.

Pyrophoricity

In the daily use and handling of zirconium dinitrate oxide during which continuous exposure to air can occur, no spontaneous ignition is observed. The absence of structural alerts furthermore confirms that it is highly unlikely that zirconium dinitrate oxide has pyrophoric properties.

Flammability in contact with water

Zirconium dinitrate oxide is used as aqueous solution. It is soluble in water and known to form a stable mixture with water.

Under conditions where zirconium dinitrate oxide is in contact with water no ignition and/or liberation of flammable gases is observed. The absence of structural alerts furthermore confirms that it is highly unlikely that zirconium dinitrate oxide is flammable in contact with water.

Flammability

Inorganic substances in which the elements other than oxygen are in their highest possible oxidation state are incapable of further reaction with oxygen and can thus be designated as non-flammable. The oxidation states of zirconium and nitrogen in zirconium dinitrate oxide are (4+) and (5+), respectively. These are the highest oxidation states of zirconium and nitrogen, respectively, and thus zirconium dinitrate oxide can be considered as non-flammable. Moreover, when zirconium dinitrate oxide is heated it decomposes over successive dehydration phases. This decomposition becomes significant at approximately 90°C and - in the end - results in the formation of zirconium dioxide. Decomposition is an endothermic reaction making the substance not liable to burning.

Justification for classification or non-classification

Following the above assessment it is concluded that zirconium dinitrate oxide is non-flammable and should thus not be classified for this endpoint under the CLP regulation.