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 ferrioxalate Potassium ferrioxalate Potassium ferrioxalate, also known as potassium trisoxalatoferrate(III), is a chemical compound with the formula [], where iron is in the +3 oxidation state. It is an octahedral transition metal complex in which three bidentate oxalate ions are bound to an iron center. Potassium acts as a counterion, balancing the −3 charge of the complex. Crystals of the trihydrated form of the complex, []·3, are emerald green in color. In solution, the salt dissociates to give the ferrioxalate anion, [], which appears fluorescent green in color. Potassium ferrioxalate is often used in chemical actinometry, i.e. the measure of light