The boron group are the chemical elements in group 13 of the periodic table, comprising boron (B), aluminium (Al), gallium (Ga), indium (In), thallium (Tl), and perhaps also the chemically uncharacterized ununtrium (Uut). The elements in the boron group are characterized by having three electrons in their outer energy levels (valence layers). These elements have also been referred to as icosagens and triels.