Hexachloroborazine

Hexachloroborazine
Names
IUPAC name
2,2,4,4,6,6-hexachloro-1,3,5,2,4,6-triazatriborinane
Other names
  • Hexachloroborazole
  • B-Trichloroborazine
  • Perchloroborazine
Identifiers
3D model (JSmol)
  • InChI=1S/B3Cl6N3/c4-1-10(7)2(5)12(9)3(6)11(1)8
    Key: TXTZMNUFKFLXLL-UHFFFAOYSA-N
  • B1(N(B(N(B(N1Cl)Cl)Cl)Cl)Cl)Cl
Properties
B3Cl6N3
Molar mass 287.15 g·mol−1
Appearance white crystals
Density g/cm3
Melting point 95 °C (203 °F; 368 K)
Hazards
Flash point °C
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Hexachloroborazine is an inorganic compound with the chemical formula B3Cl6N3.[1][2] This is a fully chlorinated derivative of borazine (B3N3H6), 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 (C6Cl6), 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]

3BCl3 + 3NCl3 ⟶ B3Cl6N3 + 6Cl2

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

  1. ^ Khan, Raju; Barua, Shaswat (5 November 2019). Two-Dimensional Nanostructures for Biomedical Technology: A Bridge between Material Science and Bioengineering. Elsevier. p. 49. ISBN 978-0-12-817651-1. Retrieved 8 March 2026.
  2. ^ Addison, C. C. (1976). Inorganic Chemistry of the Main-Group Elements: Volume 3. Royal Society of Chemistry. p. 152. ISBN 978-0-85186-772-4. Retrieved 8 March 2026.
  3. ^ Molecular Structure by Diffraction Methods. Royal Society of Chemistry. 1974. p. 119. ISBN 978-0-85186-517-1. Retrieved 8 March 2026.
  4. ^ 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. Retrieved 8 March 2026.
  5. ^ 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. Retrieved 8 March 2026.
  6. ^ Haasnoot, J. G.; Verschoor, G. C.; Romers, C.; Groeneveld, W. L. (15 July 1972). "On the crystal and molecular structure of hexachloroborazine". Acta Crystallographica Section B: Structural Crystallography and Crystal Chemistry. 28 (7): 2070–2073. doi:10.1107/S0567740872005540. ISSN 0567-7408. Retrieved 8 March 2026.
  7. ^ 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. Retrieved 8 March 2026.
  8. ^ 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. Retrieved 8 March 2026.