Amphoterism

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