Cobalt(II) Oxide is a chemical compound with the formula CoO. It consists of cobalt in a +2 oxidation state and oxygen. This black solid is commonly used in ceramics, glass, and as a pigment due to its vibrant blue color when mixed with other materials. In addition to its industrial applications, Cobalt(II) Oxide is also important in the production of rechargeable batteries, particularly in the lithium-ion variety. It can be produced through various methods, including the thermal decomposition of cobalt salts or by reacting cobalt with oxygen at high temperatures.