Aluminium nitrate

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Aluminium nitrate
Image:Aluminium nitrate.jpg
General
Systematic name	Aluminium nitrate
Molecular formula	Al(NO₃)₃
Molar mass	212.9962 g/mol
Appearance	colorless to white solid, hygroscopic
CAS Number	17473-90-0 (anhydrous), 7784-27-2 (nonahydrate)
Properties
Density and phase	>1 g/cm³
Solubility in water	60.0 g/100 ml (0°C)
Melting point	73.89°C (346.89 K)
Boiling point	Decomposes at 302°C (575 K)
Hazards
MSDS	External MSDS
Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) Infobox disclaimer and references

Aluminium nitrate is a salt of aluminium and nitric acid, existing normally as a crystalline hydrate, most commonly as aluminium nitrate nonahydrate, Al(NO₃)₃·9H₂O, with a molecular formula weight of 375.13.

[edit] Synthesis

Aluminium nitrate can be easily prepared by the reaction of aluminum hydroxide with nitric acid.

The synthesis from aluminium metal has many problems since aluminium is not attacked by nitric acid because of its protective oxide layer. The process involves an initial basic attack with KOH, followed by partial neutralization with nitric acid to precipitate the hydroxide. The hydroxide is then filtered and washed througly to remove soluble potassium nitrate. After this, the filtered aluminium hydroxide is reacted with excess nitric acid. The aluminium nitrate is then precipitated with a 10% methanol, 90% isobutanol solution and dried with dry air. The crystals are very deliquescent and must be stored in dry conditions.

[edit] Uses

Aluminium nitrate is a strong oxidizing agent. It is used in tanning leather, antiperspirants, corrosion inhibitors, extraction of uranium, petroleum refining, and as a nitrating agent. It is used in the laboratory and classroom such as in the reaction Al(NO₃)₃ + 3NaOH --> Al(OH)₃ + 3NaNO₃