Nickel Oxide

Nickel oxide is a chemical compound composed of nickel and oxygen, with the chemical formula NiO. It is a dark greenish-gray solid that can exist in several different crystal structures, including cubic, hexagonal, and rhombohedral.

Nickel oxide is insoluble in water and non-flammable. It is commonly used as a catalyst in various chemical reactions, such as the production of hydrogen gas from ethanol. It is also used in the manufacture of batteries, ceramics, and pigments.

Nickel oxide has a high melting point of approximately 1984°C and a density of 6.67 g/cm³. It is a semiconductor material, which means it has an electrical conductivity between that of a conductor and an insulator. Its electrical conductivity can be increased by doping with other materials, such as lithium or cobalt.

Nickel oxide can react with acids to produce soluble nickel salts, such as nickel chloride or nickel sulfate. It can also react with reducing agents to form metallic nickel. When heated in air, nickel oxide can decompose into nickel metal and oxygen gas.

Overall, nickel oxide is an important industrial compound with a variety of applications, particularly in catalysis and materials science.