alum
Alum (fán) is a variety of metal sulfate hydrate crystallization, and sometimes also refers to a large class of formula for the A2SO4 · B23 · 24H2O (ie AB2 · 12H2O) hydrate sulfate salt (English: Alum). Alum (potassium alum, KAl2 · 12H2O) is the most common alum. ...