Dibromine monoxide
Dibromine monoxide | |
---|---|
IUPAC name | Oxygen dibromide[note 1] |
Other names | Bromine(I) oxide Hypobromous anhydride Dibromooxidane Dibromidooxygen |
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 | [ | ]
ChemSpider | |
Properties[3][4] | |
Chemical formula | Br2O |
Molar mass | 175.81 g mol−1 |
Appearance | dark brown solid |
Density | 4.10 g cm−3 (crystal) |
Melting point |
−17.5 °C (255.7 K) decomp. |
Structure[4] | |
Space group | Pc21n (No. 33) |
Lattice constant | a = 390.4(1) pm, b = 686.2(1) pm, c = 1062.2(2) pm |
Thermochemistry[5] | |
Std enthalpy of formation ΔfH |
+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.[3][6] It is prepared by the reaction of bromine with mercury(II) oxide[7][8] or by the low temperature decomposition of bromine dioxide in vacuo.[9][10] Other routes include the photolysis of mixtures of oxygen and bromine vapour[11][12] and the reaction of BrOTeF5 with water.[4]
Structure
Dibromine monoxide has a bent C2v structure in the vapour phase, as expected from VSEPR theory, with r(Br–O) = 184.29(20) pm, θ(Br–O–Br) = 112.24(20)°.[12] 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)°.[4] Solid Br2O has also been studied by infrared spectroscopy[11][13][14][15] and by EXAFS.[15]
Reactivity
Dibromine monoxide is a strong oxidizing agent, converting iodine to diiodine pentoxide and benzene to 1,4-benzoquinone.[3] It is formally the anhydride of hypobromous acid, and gives the hypobromite ion BrO− in alkaline solution.[3]
Notes and references
Notes
- ↑ Although oxygen is more electronegative than bromine on the normal numerical scales,[1] it appears after the halogens on the conventional electronegativity series used in inorganic nomenclature.[2] Hence, OBr2 is considered a bromide of oxygen, and not an oxide of bromine, for nomenclature purposes.
References
- ↑ Allred, A. L. Electronegativity values from thermochemical data. J. Inorg. Nucl. Chem. 1961, 17 (3–4), 215–21. DOI: 10.1016/0022-1902(61)80142-5.
- ↑ Nomenclature of Inorganic Chemistry; IUPAC Recommendations 2005; Royal Society of Chemistry: Cambridge, 2005; p 260. ISBN 0-85404-438-8, <http://www.iupac.org/publications/books/rbook/Red_Book_2005.pdf>.
- ↑ 3.0 3.1 3.2 3.3 Greenwood, Norman N.; Earnshaw, A. Chemistry of the Elements; Pergamon: Oxford, 1984; pp 996–97. ISBN 0-08-022057-6.
- ↑ 4.0 4.1 4.2 4.3 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.
- ↑ 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.
- ↑ Cotton, F. Albert; Wilkinson, Geoffrey Advanced Inorganic Chemistry, 5th ed.; Wiley-Interscience: New York, 1988; p 562. ISBN 0-471-84997-9.
- ↑ 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.
- ↑ 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.
- ↑ Schwarz, R.; Wiele, H. Über das Bromoxyd Br2O. Naturwissenschaften 1938, 26 (45), 742. DOI: 10.1007/BF01774152.
- ↑ Schwarz, Robert; Wiele, Heinz Zur Kenntnis der Bromoxyde (II. Mitteilung). J. Prakt. Chem. 1938, 152 (3–6), 157–76. DOI: 10.1002/prac.19391520306.
- ↑ 11.0 11.1 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.
- ↑ 12.0 12.1 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.
- ↑ 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.
- ↑ 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.
- ↑ 15.0 15.1 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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