Alum
An alum is a type of chemical compound, usually a hydrated double sulfate salt of aluminium with the general formula XAl₂·12H₂O, such that X is a monovalent cation such... Wikipedia
An alum is a type of chemical compound, usually a hydrated double sulfate salt of aluminium with the general formula XAl₂·12H₂O, such that X is a monovalent cation such... Wikipedia