AlF63

AlF63 is not a standard chemical name, but in many contexts it is used informally to refer to the hexafluoroaluminate(III) unit [AlF6]3−, an octahedral complex in which aluminum is in the +3 oxidation state coordinated by six fluoride ligands. The conventional notation for this species is [AlF6]3− or AlF6^3−. It is not a neutral molecule but a polyatomic anion that forms salts with a variety of cations.

The [AlF6]3− anion is highly ionic and typically colorless. In solid salts, the fluoride ligands create a strongly fluorinating and highly fluorophilic environment around the aluminum center. The ion is stable in strongly fluoride-rich media and in many ionic liquids and molten salts used in fluorometallurgy. In aqueous solutions, strong hydrolysis can occur, releasing fluoride and forming aluminum hydroxide or other hydrolysis products. The Al–F bonds are strongly covalent-ionic in character, contributing to the stability of the octahedral coordination.

Formation and occurrence: the hexafluoroaluminate(III) anion appears in salts derived from aluminum sources dissolved in fluoride media, such as certain cryolite-derived systems and fluoride melts. It can pair with alkali and alkaline earth cations, organic cations, or other counterions to give a variety of salts, including those used in research on fluorometallate chemistry and advanced electrolyte systems.

Uses and relevance: [AlF6]3−-containing salts are studied for applications in non-aqueous electrolytes, fluorine chemistry, and catalysis. The related neutral compound aluminum fluoride (AlF3) is a separate material with different properties and applications, including use as a flux in aluminum production and a catalyst support. Safety: fluoride species are corrosive and can release HF on hydrolysis, so appropriate handling and shielding are required.