Boron suboxide (chemical formula B6O) is a solid compound of boron and oxygen. Its structure is built of eight icosahedra at the apexes of the rhombohedral unit cell (space group R3-m). Each icosahedron is composed of twelve boron atoms. Two oxygen atoms are located in the interstices along the [111] rhombohedral direction. Due to its short interatomic bond lengths and strongly covalent character, B6O displays a range of outstanding physical and chemical properties such as great hardness (close to that of diamond, rhenium diboride and boron nitride), low mass density, high thermal conductivity, high chemical inertness, and excellent wear resistance[3].

Carbon suboxide, or tricarbon dioxide, is an oxide of carbon with chemical formula C3O2 or O=C=C=C=O. Its four cumulative double bonds make it a cumulene. It is one of the stable members of the series of linear oxocarbons O=Cn=O, which also includes carbon dioxide (CO2) and pentacarbon dioxide (C5O2)

Lead suboxide (chemical formula B6O) is a solid compound of boron and oxygen. Its structure is built of eight icosahedra at the apexes of the rhombohedral unit cell (space group R3-m). Each icosahedron is composed of twelve boron atoms. Two oxygen atoms are located in the interstices along the [111] rhombohedral direction. Due to its short interatomic bond lengths and strongly covalent character, B6O displays a range of outstanding physical and chemical properties such as great hardness (close to that of diamond, rhenium diboride and boron nitride), low mass density, high thermal conductivity, high chemical inertness, and excellent wear resistance[3].