Metal compounds are substances formed when metal elements combine with nonmetals or other metals. These compounds often exhibit unique properties, such as conductivity and malleability, which are characteristic of metals. Common examples include sodium chloride (table salt) and iron oxide (rust). In metal compounds, the metal atoms typically lose electrons, forming positive ions, while nonmetals gain electrons to form negative ions. This transfer of electrons leads to ionic bonds, which hold the compound together. Understanding metal compounds is essential in fields like chemistry and materials science, where they are used in various applications, from construction to electronics.