Chemistry:Hexachloroborazine
Hexachloroborazine is an inorganic compound with the chemical formula B
3Cl
6N
3.[1][2] This is a fully chlorinated derivative of borazine (B
3N
3H
6), a cyclic compound often referred to as "inorganic benzene" due to its structural and electronic similarity to benzene.
Structure
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 B–N bond lengths are approximately 1.44 Å, intermediate between single and double bonds, indicating significant π-delocalization across the ring. The molecule possesses D3h symmetry and is isoelectronic and isostructural with hexachlorobenzene (C
6Cl
6), though the electronic distribution differs due to the polarity of the B–N bonds.[3][4]
Synthesis
Hexachloroborazine was first prepared by thermal decomposition of dichloroborazide at 200 °C. 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 °C.[5]
- 3BCl
3 + 3NCl
3 ⟶ B
3Cl
6N
3 + 6Cl
2
- 3BCl
Physical properties
The compound forms white powder that crystallizes in the trigonal crystal system in the space group R3.[6]
Uses
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 materials—used in the synthesis of thin films, fibers, and ceramics via chemical vapor deposition (CVD) or polymer-derived ceramic (PDC) routes.[7][8]
References
- ↑ Khan, Raju; Barua, Shaswat (5 November 2019) (in en). Two-Dimensional Nanostructures for Biomedical Technology: A Bridge between Material Science and Bioengineering. Elsevier. p. 49. ISBN 978-0-12-817651-1. https://books.google.com/books?id=-5O8DwAAQBAJ&dq=%22hexachloroborazine%22&pg=PA49. Retrieved 8 March 2026.
- ↑ Addison, C. C. (1976) (in en). Inorganic Chemistry of the Main-Group Elements: Volume 3. Royal Society of Chemistry. p. 152. ISBN 978-0-85186-772-4. https://books.google.com/books?id=HZkKPQDUU8sC&dq=%22hexachloroborazine%22&pg=RA1-PA152. Retrieved 8 March 2026.
- ↑ (in en) Molecular Structure by Diffraction Methods. Royal Society of Chemistry. 1974. p. 119. ISBN 978-0-85186-517-1. https://books.google.com/books?id=igOu7CvzSecC&dq=%22hexachloroborazine%22&pg=PA119. Retrieved 8 March 2026.
- ↑ Gopinathan, M. S.; Whitehead, M. A.; Coulson, C. A.; Carruthers, J. R.; Rollett, J. S. (1 March 1974). "A reinvestigation of the crystal and molecular structure of hexachloroborazine". Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry 30 (3): 731–737. doi:10.1107/S0567740874003608. ISSN 0567-7408. https://onlinelibrary.wiley.com/doi/abs/10.1107/S0567740874003608. Retrieved 8 March 2026.
- ↑ Haasnoot, J. G.; Groeneveld, W. L. (1 December 1967). "Preparation and properties of hexachloroborazine". Inorganic and Nuclear Chemistry Letters 3 (12): 597–601. doi:10.1016/0020-1650(67)80034-5. ISSN 0020-1650. https://www.sciencedirect.com/science/article/abs/pii/0020165067800345. Retrieved 8 March 2026.
- ↑ Haasnoot, J. G.; Verschoor, G. C.; Romers, C.; Groeneveld, W. L. (15 July 1972). "On the crystal and molecular structure of hexachloroborazine" (in en). Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry 28 (7): 2070–2073. doi:10.1107/S0567740872005540. ISSN 0567-7408. https://journals.iucr.org/paper?S0567740872005540. Retrieved 8 March 2026.
- ↑ Constant, G.; Feurer, R. (1 November 1981). "Preparation and characterization of thin protective films in silica tubes by thermal decomposition of hexachloroborazine". Journal of the Less Common Metals 82: 113–118. doi:10.1016/0022-5088(81)90206-X. ISSN 0022-5088. https://www.sciencedirect.com/science/article/abs/pii/002250888190206X. Retrieved 8 March 2026.
- ↑ Sun, Nijuan; Wang, Chi; Jiao, Liying; Zhang, Juan; Zhang, Dahai (1 January 2017). "Controllable coating of boron nitride on ceramic fibers by CVD at low temperature". Ceramics International 43 (1, Part B): 1509–1516. doi:10.1016/j.ceramint.2016.10.123. ISSN 0272-8842. https://www.sciencedirect.com/science/article/abs/pii/S0272884216318880. Retrieved 8 March 2026.
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