Boron has electronic configuration [He]2s²2p¹, and main formal oxidation state +3.

Its bonding is mainly covalent, and it forms compounds with three bonds, and therefore six electrons in its valence shell: It is electron deficient.

The bonding orbitals are sp² hybrid orbitals, and the remaining p-orbital on B acts as a pi-acceptor orbital, eg. in BF₃ , where the back donation of p-electrons from F to B forms pπ-pπ bonds.

Ionic interactions also occur, and lead to a shortening and strengthening of bonds, eg. in BF₄^- , where pπ-pπ bonds are absent.

Occurrence

Main sources of Boron are hydrated oxides, like borax (Na₂B₄O₅(OH)₄.8H₂O). Aluminium, the second element in Group 13, has the primary ore bauxite, containing hydrated aluminium oxide (Al₂O₃.H₂O).