Potassium monoxide

Potassium Oxide (Potassium Monoxide). K20, mw 94.20, white, loose, deliq powd, mp 350° (decompn), d 2.32g/cc at 0°, Reacts with w very readily to form KOH with evotn of 75 kcal/mole. V sol in w, si sol in ethanol and eth. Prepn is by mildly heating carefully purified K in the presence of pure dry air. Excess K is distd off at 350° under high vacuum. The K20 is 99.5% pure. Also produced when K compds are burned in pyrots... 

Potassium reacts with oxygen or air forming three oxides potassium monoxide, KaO potassium peroxide, KaOa and potassium superoxide, KOa. The nature of the product depends on oxygen supply. In limited supply of oxygen potassium monoxide is formed, while in excess oxygen, superoxide is... 

Reaction with potassium nitrate yields potassium monoxide and nitrogen lOK + 2KNO3 6K2O + N2... 

Potassium monoxide, K20.—The monoxide is formed by incomplete oxidation of potassium by dry oxygen at reduced pressure, and removal of the excess of metal by distillation in vacuum.1 The product forms microscopic octahedra, which become pale-yellow at 200° C., and have a density of 2-32 at 0° C. Above 400° C. in vacuum it is decomposed into the metal and the peroxide. The heat of formation of the monoxide from its elements is 86-80 Cal.2 It is reduced by hydrogen to the hydride and hydroxide. With water it reacts energetically to form the hydroxide, the heat of solution being 75-0 Cal.3 It also combines with fluorine, chlorine, and iodine. The heat of formation from the elements is 86-8 Cal.3... 

When heated in air, potassium forms three oxides potassium monoxide, KjO peroxide, KjOj and superoxide, KOj. Potassium reduces the oxides, hydroxides and salts of many heavy metals to the metallic state, and at high temperatures it decomposes silicates (e.g., glass, porcelain, mica). 

---