ferric rubidium alum
1Alum — This article is about the chemical compound. For other uses, see Alum (disambiguation). Bulk alum Alum (  / …
2alum — A double sulfate of aluminum and of an alkaline earth element or ammonium; chemically, an a. is any one of the markedly astringent double salts formed by a combination of a sulfate of aluminum, iron, manga …
