Dibromine monoxide

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Dibromine monoxide
IUPAC name Oxygen dibromide
Other names Hypobromous anhydride
Identifiers
InChI InChI=1/Br2O/c1-3-2
InChIKey HJCMMOODWZOXML-UHFFFAOYAD
Standard InChI InChI=1S/Br2O/c1-3-2
Standard InChIKey HJCMMOODWZOXML-UHFFFAOYSA-N
CAS number [21308-80-5]
ChemSpider 10686917
Properties[1][2]
Chemical formula Br2O
Molar mass 175.81 g mol−1
Appearance dark brown solid
Density 4.10 g cm−3
Melting point

−17.5 °C (255.7 K) decomp.

Structure[2]
Space group Pc21n (No. 33)
Lattice constant a = 390.4(1) pm, b = 686.2(1) pm, c = 1062.2(2) pm
Thermochemistry[3]
Std enthalpy of formation ΔfHo298 +107.1(35) kJ mol−1
Related compounds
Other cations Difluorine monoxide
Dichlorine monoxide
Other oxides of bromine Bromine dioxide
Other compounds Hypobromous acid
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

Dibromine monoxide, Br2O, is a binary compound of bromine and oxygen. The dark brown solid is unstable at room temperature.[1][4] It is prepared by the reaction of bromine with mercury(II) oxide[5][6] or by the low temperature decomposition of bromine dioxide in vacuo.[7][8]

Structure

Dibromine monoxide has a bent C2v structure in the vapour phase, with r(Br–O) = 184.29(20) pm, θ(Br–O–Br) = 112.24(20)°.[9] In the solid state, the symmetry is lower, with slightly different Br–O distances (185.7(5), 187.5(5) pm) and θ(Br–O–Br) = 114.2(2)°.[2] Solid Br2O has also been studied by infrared spectroscopy[10][11][12][13] and by EXAFS.[13]

Notes and references

Notes

References

  1. 1.0 1.1 Greenwood, Norman N.; Earnshaw, A. Chemistry of the Elements; Pergamon: Oxford, 1984; pp 996–97. ISBN 0-08-022057-6.
  2. 2.0 2.1 2.2 Hwang, In-Chur; Kuschel, Raimund; Seppelt, Konrad Structures of Bromine Oxygen Compounds. Z. Anorg. Allg. Chem., 623 (1–6), 379–83. DOI: 10.1002/zaac.19976230160.
  3. Thorn, R. Peyton, Jr.; Monks, Paul S.; Stief, Louis J.; Kuo, Szu-Cherng; Zhang, Zhengyu; Klemm, R. Bruce Photoionization Efficiency Spectrum, Ionization Energy, and Heat of Formation of Br2O. J. Phys. Chem. 1996, 100 (30), 12199–203. DOI: 10.1021/jp960405z.
  4. Cotton, F. Albert; Wilkinson, Geoffrey Advanced Inorganic Chemistry, 5th ed.; Wiley-Interscience: New York, 1988; p 562. ISBN 0-471-84997-9.
  5. Zintl, E.; Rienäcker, G. Über die Existenz eines flüchtigen Bromoxyds. Ber. Dtsch. Chem. Ges. B 1930, 63 (5), 1098–1104. DOI: 10.1002/cber.19300630516.
  6. Brenschede, W.; Schumacher, H.-J. Über die Darstellung und einige Eigenschaften eines Bromoxyds von der Formel Br2O. Z. Anorg. Allg. Chem. 1936, 226 (4), 370–84. DOI: 10.1002/zaac.19362260409.
  7. Schwarz, R.; Wiele, H. Über das Bromoxyd Br2O. Naturwissenschaften 1938, 26 (45), 742. DOI: 10.1007/BF01774152.
  8. Schwarz, Robert; Wiele, Heinz Zur Kenntnis der Bromoxyde (II. Mitteilung). J. Prakt. Chem. 1938, 152 (3–6), 157–76. DOI: 10.1002/prac.19391520306.
  9. Müller, Holger S. P.; Cohen, Edward A. Dibromine monoxide, Br2O: The rotational spectrum and molecular properties. J. Chem. Phys. 1997, 106 (20), 8344–54. DOI: 10.1063/1.473920.
  10. Campbell, C.; Jones, J. P. M.; Turner, J. J. Spectroscopic studies of bromine oxides: the infrared spectrum of solid bromide monoxide. Chem. Commun. (London) 1968 (15), 888–89. DOI: 10.1039/C19680000888.
  11. Tevault, D.; Walker, N.; Smardzewski, R.; Fox, W. Infrared spectra of the BrO and OBrO free radicals and of BrOBr and BrBrO molecules in Solid Argon at 10K. J. Phys. Chem. 1978, 82 (25), 2733–36. DOI: 10.1021/j100514a022.
  12. Allen, S. D.; Poliakoff, M.; Turner, J. J. Photochemistry of an ozone-bromine complex; the IR spectrum of matrix isolated Br2O. J. Mol. Struct. 1987, 157 (1–3), 1–15. DOI: 10.1016/0022-2860(87)87078-3.
  13. 13.0 13.1 Levason, William; Ogden, J. Steven; Spicer, Mark D.; Young, Nigel A. Characterization of dibromine monoxide (Br2O) by bromine K-edge EXAFS and IR spectroscopy. J. Am. Chem. Soc. 1990, 112 (3), 1019–22. DOI: 10.1021/ja00159a019.

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