Nickel sulfides are chemical compounds composed of nickel and sulfur. They typically occur in nature as minerals, such as pentlandite and millerite, and are important sources of nickel for industrial use. These compounds can be found in various geological settings, often associated with magmatic and hydrothermal processes. In addition to their role in nickel extraction, nickel sulfides have applications in electronics and catalysis. They can also be studied for their potential use in batteries and other energy storage systems. Understanding their properties helps in developing more efficient methods for nickel recovery and utilization.