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Physical & Chemical properties

Flammability

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Description of key information

Waiving (study scientifically unjustified).

Key value for chemical safety assessment

Flammability:
non flammable

Additional information

Justification for classification or non-classification

No classification required.Ammonium octamolybdate is not a flammable solid. It does not exhibit pyrophoric properties, nor does it react with water under formation of flammable reaction products.

Flammability is not considered to be relevant for this inorganic compound in which the metal is in its highest possible oxidation state (+VI for Mo), 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). Further, an experimental study on the flammability of molybdenum metal powder has shown that molybdenum is not flammable in the elemental state. In conclusion, flammability cannot be expected for ammonium octamolybdate.

Pyrophoric properties are not plausible, since ammonium octamolybdate is stable at ambient temperature (decomposition temperature >=200°C). During thermogravimetric experiments (heating up to ca. 400°C) no observation indicating ignition were made. 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. Furthermore, long-term industrial experience in handling shows that ammonium octamolybdate does not show any pyrophoric properties.

Flammability in contact with water is not considered to be relevant, 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, recent experimental testing for water solubility has also not reported any formation of gases. In contrast, ammonium octamolybdate slowly dissolves in water at ca. 1 g/L.