Nickel oxide is a chemical compound composed of nickel and oxygen, with the formula NiO. It appears as a green or black powder and is commonly used in various applications, including ceramics, glass, and as a catalyst in chemical reactions. Nickel oxide is also utilized in the production of nickel-based batteries. In addition to its industrial uses, nickel oxide plays a role in electronics, particularly in the manufacture of thin-film transistors and solar cells. It is important to handle nickel oxide with care, as it can be toxic if inhaled or ingested, necessitating proper safety measures during its use.