Difference between revisions of "Perbromic acid"

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'''Perbromic acid''', HBrO<sub>4</sub>, is an [[oxoacid]] of [[bromine]]. It is a [[strong acid]] that is not known as a molecular species.<ref name="G&E"/><ref name="Kirk-Othmer">{{Kirk-Othmer | first1 = S. D. | last1 = Ukeles | first2 = M. | last2 = Freiberg | contribution = Bromine, Inorganic Compounds | doi = 10.1002/0471238961.021815131001031 | year = 2002}}.</ref>
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'''Perbromic acid''', HBrO<sub>4</sub>, is an [[oxoacid]] of [[bromine]]. It is a [[strong acid]] that is not known as a molecular species.<ref name="G&E"/><ref name="C&W">{{Cotton&Wilkinson5th|pages=568–69}}.</ref><ref name="Kirk-Othmer">{{Kirk-Othmer | first1 = S. D. | last1 = Ukeles | first2 = M. | last2 = Freiberg | contribution = Bromine, Inorganic Compounds | doi = 10.1002/0471238961.021815131001031 | year = 2002}}.</ref>
  
 
==Preparation==
 
==Preparation==
Perbromic acid is prepared by [[ion exchange]] of a solution of [[sodium perbromate]].<ref name="Kirk-Othmer"/><ref>{{citation | first = Evan H. | last = Appelman | title = Perbromic acid and perbromates: synthesis and some properties | journal = Inorg. Chem. | volume = 8 | issue = 2 | pages = 223–27 | year = 1969 | doi = 10.1021/ic50072a008}}.</ref><ref>{{citation | first = E. H. | last = Appelman | title = Perbromic acid and potassium perbromate | journal = Inorg. Synth. | year = 1972 | volume = 13 | pages = 1–9 | doi = 10.1002/9780470132449.ch1}}.</ref> The acid can be concentrated up to 6&nbsp;M (55%) by evaporation of water under reduced pressure: more concentrated solutions can be prepared, but are unstable.<ref name="G&E"/>
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Perbromic acid is prepared by [[ion exchange]] of a solution of [[sodium perbromate]].<ref name="Kirk-Othmer"/><ref>{{citation | first = Evan H. | last = Appelman | title = Perbromic acid and perbromates: synthesis and some properties | journal = Inorg. Chem. | volume = 8 | issue = 2 | pages = 223–27 | year = 1969 | doi = 10.1021/ic50072a008}}.</ref><ref>{{citation | first = E. H. | last = Appelman | title = Perbromic acid and potassium perbromate | journal = Inorg. Synth. | year = 1972 | volume = 13 | pages = 1–9 | doi = 10.1002/9780470132449.ch1}}.</ref> The acid can be concentrated up to 6&nbsp;M (55%) by evaporation of water under reduced pressure: more concentrated solutions can be prepared, but are unstable.<ref name="G&E"/><ref name="C&W"/>
  
 
==Properties==
 
==Properties==
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The properties of perbromic acid are very similar to those of [[perchloric acid]].<ref name="G&E"/><ref name="Kirk-Othmer"/> It is a [[strong acid]], completely dissociated in aqueous solution.<ref name="Kirk-Othmer"/> A solid hydrate, believed to be HBrO<sub>4</sub>·2H<sub>2</sub>O, has been prepared:<ref name="G&E"/><ref name="C&W"/> by comparison with the perchloric acid [[azeotrope]],<ref>{{citation | first = Ivar | last = Olovsson | title = Hydrogen-Bond Studies. XXIX. Crystal Structure of Perchloric Acid Dihydrate, {{nowrap|H<sub>5</sub>O<sub>2</sub><sup>+</sup>ClO<sub>4</sub><sup>−</sup>}} | journal = J. Chem. Phys. | volume = 49 | issue = 3 | pages = 1063–67 | year = 1968 | doi = 10.1063/1.1670193}}.</ref> also of composition HClO<sub>4</sub>·2H<sub>2</sub>O (71.6% HClO<sub>4</sub>), this should almost certainly be formulated as {{nowrap|[(H<sub>2</sub>O)<sub>2</sub>H]<sup>+</sup>[BrO<sub>4</sub>]<sup>−</sup>}}.
  
 
==Notes and references==
 
==Notes and references==

Revision as of 10:10, 5 January 2011

Perbromic acid
IUPAC name Perbromic acid[note 1]
Other names Bromic(VII) acid
Hydroxy-λ7-bromanetrione
Hydroxidotrioxidobromine
Identifiers
InChI InChI=1/BrHO4/c2-1(3,4)5/h(H,2,3,4,5)
InChIKey LLYCMZGLHLKPPU-UHFFFAOYAZ
Standard InChI InChI=1S/BrHO4/c2-1(3,4)5/h(H,2,3,4,5)
Standard InChIKey LLYCMZGLHLKPPU-UHFFFAOYSA-N
CAS number [19445-25-1]
ChemSpider 167074
Properties[2]
Chemical formula HBrO4
Molar mass 144.91 g mol−1
Acidity (pKa) < 0
Related compounds
Other perhalic acids Perchloric acid
Periodic acid
Other compounds Hydrobromic acid
Hypobromous acid
Bromous acid
Bromic acid
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

Perbromic acid, HBrO4, is an oxoacid of bromine. It is a strong acid that is not known as a molecular species.[2][3][4]

Preparation

Perbromic acid is prepared by ion exchange of a solution of sodium perbromate.[4][5][6] The acid can be concentrated up to 6 M (55%) by evaporation of water under reduced pressure: more concentrated solutions can be prepared, but are unstable.[2][3]

Properties

The properties of perbromic acid are very similar to those of perchloric acid.[2][4] It is a strong acid, completely dissociated in aqueous solution.[4] A solid hydrate, believed to be HBrO4·2H2O, has been prepared:[2][3] by comparison with the perchloric acid azeotrope,[7] also of composition HClO4·2H2O (71.6% HClO4), this should almost certainly be formulated as [(H2O)2H]+[BrO4].

Notes and references

Notes

  1. Perbromic acid is a retained name in IUPAC nomenclature.[1]

References

  1. Nomenclature of Inorganic Chemistry; IUPAC Recommendations 2005; Royal Society of Chemistry: Cambridge, 2005; p 287. ISBN 0-85404-438-8, <http://www.iupac.org/publications/books/rbook/Red_Book_2005.pdf>.
  2. 2.0 2.1 2.2 2.3 2.4 Greenwood, Norman N.; Earnshaw, A. Chemistry of the Elements; Pergamon: Oxford, 1984; pp 1020–22. ISBN 0-08-022057-6.
  3. 3.0 3.1 3.2 Cotton, F. Albert; Wilkinson, Geoffrey Advanced Inorganic Chemistry, 5th ed.; Wiley-Interscience: New York, 1988; pp 568–69. ISBN 0-471-84997-9.
  4. 4.0 4.1 4.2 4.3 Ukeles, S. D.; Freiberg, M. Bromine, Inorganic Compounds. In Kirk-Othmer Encyclopedia of Chemical Technology; John Wiley: New York, 2002. DOI: 10.1002/0471238961.021815131001031.
  5. Appelman, Evan H. Perbromic acid and perbromates: synthesis and some properties. Inorg. Chem. 1969, 8 (2), 223–27. DOI: 10.1021/ic50072a008.
  6. Appelman, E. H. Perbromic acid and potassium perbromate. Inorg. Synth. 1972, 13, 1–9. DOI: 10.1002/9780470132449.ch1.
  7. Olovsson, Ivar Hydrogen-Bond Studies. XXIX. Crystal Structure of Perchloric Acid Dihydrate, H5O2+ClO4. J. Chem. Phys. 1968, 49 (3), 1063–67. DOI: 10.1063/1.1670193.

External links

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