Metal oxides are compounds formed when metals react with oxygen. They typically consist of a metal element combined with oxygen, resulting in a solid substance. Common examples include iron oxide, which is rust, and zinc oxide, used in sunscreens. These compounds can exhibit various properties, such as conductivity and reactivity, depending on the metal involved. Metal oxides play significant roles in various industries and applications. They are used in electronics, ceramics, and catalysis. For instance, titanium dioxide is widely used as a pigment in paints and coatings due to its brightness and opacity. Additionally, some metal oxides are important in environmental processes, such as catalytic converters in vehicles that reduce harmful emissions.