The formation, precipitation and structural characterisation of hydroxyaluminosilicates formed in the presence of fluoride and phosphate

Hydroxyaluminosilicates (HAS) are important secondary mineral phases formed by the reaction of silicic acid with aluminium. There are two discrete forms of HAS (HASA and HASB) and we now show the accomodation of fluorine into both forms through its replacement of hydroxyl groups coordinated to octahedral aluminium.