The molecule is a hydrate resulting from the the formal combination of anhydrous aluminium sulfate with approximately 18 mol eq. of water. The commercial product usually contains 5-10% less water than theory. It is one of the commonest hydrates of aluminium sulfate. It is a hydrate and an aluminium sulfate. It contains an aluminium sulfate (anhydrous).
dialuminum;trisulfate;octadecahydrate