Hexachloroborazine is an inorganic compound with the chemical formula . This is a fully chlorinated derivative of borazine (), a cyclic compound often referred to as "inorganic benzene" due to its structural and electronic similarity to benzene.
Hexachloroborazine features a planar, six-membered ring with alternating boron and nitrogen atoms, analogous to the carbon ring in benzene. Each boron atom is bonded to one chlorine atom, while each nitrogen atom bears a lone pair of electrons. The BâÂÂN bond lengths are approximately 1.44 à, intermediate between single and double bonds, indicating significant ÃÂ-delocalization across the ring. The molecule possesses D<sub>3h</sub> symmetry and is isoelectronic and isostructural with hexachlorobenzene (), though the electronic distribution differs due to the polarity of the BâÂÂN bonds.
Hexachloroborazine was first prepared by thermal decomposition of dichloroborazide at 200 ðC. However, this method gives low yields and is very dangerous due to the risk of explosions. A more advantageous method is the reaction of boron trichloride and nitrogen trichloride in carbon tetrachloride at 45 ðC.
The compound forms white powder that crystallizes in the trigonal crystal system in the space group R3.
Hexachloroborazine is of interest in inorganic chemistry, materials science, and the synthesis of boron nitride-based materials.
The compound is used as a precursor to boron nitride materialsâÂÂused in the synthesis of thin films, fibers, and ceramics via chemical vapor deposition (CVD) or polymer-derived ceramic (PDC) routes.