Amphoteric oxide
Oxides are compounds of metals or nonmetals with oxygen. There are four types of oxide. Amphoteric oxides are classified as metal oxides that react with both acids as well as bases to create salts and water. Amphoteric oxides, among many others, include lead oxide and zinc oxide. Examples include amino acids and proteins that have classes of amine and carboxylic acids and molecules that can be self-ionized, such as water.