- 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, manganese, chromium, or gallium with a sulfate of lithium, sodium, potassium, ammonium, cesium, or rubidium; used locally as styptics. [L. alumen]- burnt a. SYN: dried a..- dried a. a. deprived of its water of crystallization by heat; an astringent dusting powder. SYN: burnt a..
* * *al·um 'al-əm n1) either of two colorless or white crystalline double sulfates of aluminum used in medicine internally as emetics and locally as astringents and styptics:b) one consisting of an ammonium aluminum sulfate NH4Al(SO4)2·12H2O called also ammonia alum, ammonium alum2) any of various double salts isomorphous with potassium aluminum sulfate
* * *al·um (alґəm) [L. alumen] 1. an odorless, colorless crystalline substance, with local astringent and styptic properties and a sweet taste, prepared from bauxite and sulfuric acid, with the addition of ammonium (ammonium a.) or potassium (potassium a.). It is also used as an adjuvant in adsorbed vaccines and toxoids. 2. any of a group of double sulfates formed on the type of this compound.
Medical dictionary. 2011.