Amphoterism

In chemistry, an amphoteric compound is a molecule or ion that can react both as an acid as well as a base. The word is derived from the Greek word amphoteroi (ἀμφότεροι) meaning "both". Many metals (such as copper, zinc, tin, lead, aluminium, and beryllium) form amphoteric oxides or hydroxides. Amphoterism depends on the oxidation states of the oxide.