Poly Aluminium Chloride (PAC)

A group of specific aluminium salts having the general formula AlnCl(3n-m)(OH)m. It is used in cosmetics as an antiperspirant and as a coagulant in water purification. In water purification, this compound is preferred in some cases because of its high charge, which makes it more effective at destabilizing and removing suspended materials than other aluminium salts such as aluminium sulfate, aluminium chloride and various forms of poly aluminium chloride and poly aluminium chlorosulfite, in which the aluminium structure results in a lower net charge than aluminium chlorohydrate. Further, the high degree of neutralization of the HCl results in minimal impact on treated water pH when compared to other aluminium and iron salts.