Potassium tree leaves, adding water, heating, and evaporating the solution. When Humphry Davy first isolated the pure element using electrolysis in 1807, he named it "potassium", which he derived from the word potash. The symbol "K" stems from "kali", itself from the root word "alkali", which in turn comes from "" "al-qalyah" "plant ashes." In 1797, the German chemist Martin Klaproth discovered "potash" in the minerals leucite and lepidolite, and realized that "potash" was not a product of plant growth but actually contained a new element, which he proposed to call "kali". In 1807, Humphry Davy produced the element via electrolysis:
Potassium alum Potassium alum Potassium alum, potash alum, or potassium aluminium sulfate is a chemical compound: the double sulfate of potassium and aluminium, with chemical formula KAl(SO). It is commonly encountered as the dodecahydrate, KAl(SO)·12HO. It crystallizes in cubic structure with space group P a -3 and lattice parameter of 12.18 Å. The compound is the most important member of the generic class of compounds called alums, and is often called simply alum. Potassium alum is commonly used in water purification, leather tanning, dyeing, fireproof textiles, and baking powder as E number E522. It also has cosmetic uses as a deodorant, as