Aluminium fluoride

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Aluminium fluoride
Other names	Aluminium(III) fluoride Aluminium trifluoride
Identifiers
CAS number	[7784-18-1]
Properties
Molecular formula	AlF3
Molar mass	83.977 g mol−1
Appearance	white, crystalline solid odorless
Density	2.91 g cm−3, solid
Melting point	1290 °C
Solubility in water	insoluble
Hazards
EU classification	not listed
NFPA 704	0 1 0
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Aluminium fluoride is the inorganic compound with the formula AlF₃. It can be prepared by treating aluminium hydroxide or aluminium metal with HF. As a solid, its structure resembles that of rhenium trioxide, ReO₃, consisting of distorted AlF₆ octahedra.

AlF₃ is refractory, in strong contrast to the other halides of aluminium.^[1] AlCl₃, AlBr₃, and AlI₃ are dimeric in the liquid and evaporate as dimers as well. In the gas phase, at ca. 1000 °C, aluminium fluoride exists as trigonal molecules of D_3h symmetry group. The Al-F bond lengths are 163 pm.

Aluminium fluoride is an important additive during electrolyte aluminium production because it lowers the melting point of the alumina feed and increases the electrolyte's conductivity.

[edit] References

1. ^ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.

[edit] External Information

Aluminum Fluoride