Potassium (19)
- Potassium concentration in seawater is 0.39g/L (0.04% by weight), far less abundant than sodium at 10.8g/L.
- Orthoclase (Potassium Feldspar) is a common rock-forming mineral.
- Granite contains 5% potassium.
- Minerals found in large evaporate deposits (in lake bottoms and seabeds):
- Sylvite (KCl)
- Carnallite (KCl.MgCl2.6(H2O)
- Kainite (MgSO4.KCl.3H2O)
- Langbeinite (MgSO4.K2SO4)
- Polyhalite
- Metal that oxidizes rapidly in air and is very reactive with water, generating sufficient heat to ignite hydrogen emitted in the reaction.
- Agricultural fertilizers consume 95% of global potassium chemical production.
- Potassium is the second least dense metal, after Lithium.
- Potassium does not react with most hydrocarbons such as mineral oil or kerosene. It readily dissolves in liquid ammonia.
- Potassium employed as reductant: MgCl2 + 2K → Mg + 2KCl
- Potassium hydroxide reacts readily with carbon dioxide to produce Potassium Carbonate, and is used to remove traces of the gas from air.
- Potassium + Oxygen = Potassium Peroxide
- Potassium + Water = Potassium Hydroxide
- Potassium oxidizes faster than most metals and forms oxides with oxygen-oxygen bonds, as do all alkali metals, except Lithium.
- Potassium Soaps from animal fats and vegetable oils were especially prized.
- Potassium Super-Peroxide – pressure sensitive explosive that will detonate when scratched.