Cesium is a chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-golden alkali metal that is highly reactive and has a low melting point. Cesium is known for its use in atomic clocks, which are incredibly accurate timekeeping devices, as well as in various applications in chemistry, physics, and the oil industry. Due to its reactivity, cesium must be stored under oil or in an inert atmosphere to prevent it from reacting with moisture in the air.
