groupIII

Group III, historically referred to as Group IIIA in older chemical nomenclature, is the boron group of elements in the periodic table. In the modern 18-column arrangement, Group 13 includes boron (B), aluminum (Al), gallium (Ga), indium (In), thallium (Tl), and nihonium (Nh). Moscovium (Mc) is not a member of this group; it is placed in a different group in the periodic table. The elements of Group 13 lie in the p-block and share a common trend of three valence electrons.

Chemically, Group 13 elements typically exhibit an outer electron configuration of ns2np1. Their common oxidation state is +3, though heavier members show a notable tendency toward +1 due to the inert pair effect (for example, thallium more readily forms Tl+). Boron is a metalloid with strong covalent bonding and forms complex covalent networks, while aluminum, gallium, indium, and thallium are metals with more pronounced metallic character as one moves down the group. The chemistry shifts from predominantly covalent for boron to more ionic for the heavier elements in many of their compounds.

Applications and notable compounds include aluminum's widespread use in structural alloys and packaging; boron’s role in glass, ceramics, and boron-containing chemicals; gallium and indium in semiconductors and optoelectronic devices (such as gallium arsenide and indium tin oxide); and thallium in certain specialized electronics historically, although its toxicity limits its use. Nihonium is a synthetic, highly radioactive element produced in particle accelerators with no practical applications to date.

Overall, Group 13 elements show a progression from covalent network forming light metalloid behavior to metallic properties with increasing atomic number, alongside evolving oxidation states and applications.