Difference between revisions of "Perbromate"

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==History==
 
==History==
Although [[perchlorate]]s and [[periodate]]s have been known since the early nineteenth century, perbromates proved far more elusive. The first claim of preparation came in 1863,<ref>{{citation | first = Hermann | last = Kämmerer | title = Notizen | journal = J. Prakt. Chem. | year = 1863 | volume = 90 | pages = 190 | doi = 10.1002/prac.18630900126}}. {{citation | first = Hermann | last = Kaemmerer | title = Studien über die Sauerstoffverbindungen der Halogene | journal = Ann. Phys. (Berlin) | volume = 214 | issue = 11 | pages = 390–417 | year = 1869 | doi = 10.1002/andp.18692141104}}.</ref> but proved unrepeatable.<ref>{{citation | first = M. M. | last = Pattison Muir | title = Note on the perbromates | journal = J. Chem. Soc. | year = 1876 | volume = 30 | page = 469 | doi = 10.1039/JS8763000469}}.</ref><ref>{{citation | first = Guido | last = Wolfram | title = Ueber die Darstellung der Perbromsäure | journal = Justus Liebigs Ann. Chem. | year = 1879 | volume = 198 | issue = 1–2 | pages = 95–98 | doi = 10.1002/jlac.18791980107}}.</ref> Several later attempts to prepare perbromates were equally unsuccessful.<ref>{{citation | first = Ernest H. | last = Cook | title = Effect of heat on iodates and bromates. I. Potassic iodate and bromate | journal = J. Chem. Soc., Trans. | year = 1894 | volume = 65 | pages = 802–14 | doi = 10.1039/CT8946500802}}.</ref><ref>{{citation | first1 = G. M. | last1 = Bancroft | first2 = H. D. | last2 = Gesser | title = The search for perbromate—I: The thermal decomposition of bromates | journal = J. Inorg. Nucl. Chem. | year = 1965 | volume = 27 | issue = 7 | pages = 1545–56 | doi = 10.1016/0022-1902(65)80016-1}}.</ref> Several authors surmised that perbromates were fundamentally unstable.<ref>{{citation | first = Z. Z., Jr. | last = Hugus | title = The Possible Use of 4f Orbitals in Bonding: the Enhanced Stability of the Higher Oxidation States of Iodine, Tellurium and Antimony; the Non-existence of Perbromic Acid | journal = J. Am. Chem. Soc. | year = 1952 | volume = 74 | issue = 4 | pages = 1076–77 | doi = 10.1021/ja01124a502}}.</ref><ref>{{citation | first = D. S. | last = Urch | title = The perbromate problem | journal = J. Inorg. Nucl. Chem. | year = 1963 | volume = 25 | issue = 7 | pages = 771–78 | doi = 10.1016/0022-1902(63)80360-7}}.</ref>
+
Although [[perchlorate]]s and [[periodate]]s have been known since the early nineteenth century, perbromates proved far more elusive. The first claim of preparation came in 1863,<ref>{{citation | first = Hermann | last = Kämmerer | title = Notizen | journal = J. Prakt. Chem. | year = 1863 | volume = 90 | pages = 190 | doi = 10.1002/prac.18630900126}}. {{citation | first = Hermann | last = Kaemmerer | title = Studien über die Sauerstoffverbindungen der Halogene | journal = Ann. Phys. (Berlin) | volume = 214 | issue = 11 | pages = 390–417 | year = 1869 | doi = 10.1002/andp.18692141104}}.</ref> but proved unrepeatable.<ref>{{citation | first = M. M. | last = Pattison Muir | title = Note on the perbromates | journal = J. Chem. Soc. | year = 1876 | volume = 30 | page = 469 | doi = 10.1039/JS8763000469}}.</ref><ref>{{citation | first = Guido | last = Wolfram | title = Ueber die Darstellung der Perbromsäure | journal = Justus Liebigs Ann. Chem. | year = 1879 | volume = 198 | issue = 1–2 | pages = 95–98 | doi = 10.1002/jlac.18791980107}}.</ref> Several later attempts to prepare perbromates were equally unsuccessful.<ref>{{citation | first = Ernest H. | last = Cook | title = Effect of heat on iodates and bromates. I. Potassic iodate and bromate | journal = J. Chem. Soc., Trans. | year = 1894 | volume = 65 | pages = 802–14 | doi = 10.1039/CT8946500802}}.</ref><ref>{{citation | first1 = G. M. | last1 = Bancroft | first2 = H. D. | last2 = Gesser | title = The search for perbromate—I: The thermal decomposition of bromates | journal = J. Inorg. Nucl. Chem. | year = 1965 | volume = 27 | issue = 7 | pages = 1545–56 | doi = 10.1016/0022-1902(65)80016-1}}.</ref> Some authors surmised that perbromates were fundamentally unstable.<ref>{{citation | first = Z. Z., Jr. | last = Hugus | title = The Possible Use of 4f Orbitals in Bonding: the Enhanced Stability of the Higher Oxidation States of Iodine, Tellurium and Antimony; the Non-existence of Perbromic Acid | journal = J. Am. Chem. Soc. | year = 1952 | volume = 74 | issue = 4 | pages = 1076–77 | doi = 10.1021/ja01124a502}}.</ref><ref>{{citation | first = D. S. | last = Urch | title = The perbromate problem | journal = J. Inorg. Nucl. Chem. | year = 1963 | volume = 25 | issue = 7 | pages = 771–78 | doi = 10.1016/0022-1902(63)80360-7}}.</ref>
  
 
The first clear evidence of the existence of the perbromate anion came from "hot-atom" techniques. A sample of the β<sup>−</sup>-emittor [[selenium-83]] (''t''<sub>½</sub>&nbsp;= 25&nbsp;min) was prepared in the form of the [[selenate]] anion SeO{{su|b=4|p=−}} and allowed to decay into [[bromine-83]]. Approximately 14% of the <sup>83</sup>Br activity (β<sup>−</sup>, ''t''<sub>½</sub>&nbsp;= 2.4&nbsp;h) coprecipitated with [[rubidium perchlorate]], as expected for a perbromate species.<ref name="1st"/>
 
The first clear evidence of the existence of the perbromate anion came from "hot-atom" techniques. A sample of the β<sup>−</sup>-emittor [[selenium-83]] (''t''<sub>½</sub>&nbsp;= 25&nbsp;min) was prepared in the form of the [[selenate]] anion SeO{{su|b=4|p=−}} and allowed to decay into [[bromine-83]]. Approximately 14% of the <sup>83</sup>Br activity (β<sup>−</sup>, ''t''<sub>½</sub>&nbsp;= 2.4&nbsp;h) coprecipitated with [[rubidium perchlorate]], as expected for a perbromate species.<ref name="1st"/>
  
 
Electrolysis of [[lithium bromate]] at a [[platinum]] [[anode]] gave a yield of about 2% perbromate.<ref name="1st"/> Small amounts of perbromate (1–4% yield) were also formed by the [[xenon difluoride]] oxidation of bromates, while [[perxenate]], [[peroxodisulfate]] and [[ozone]] were ineffective as oxidizing agents.<ref name="1st"/>
 
Electrolysis of [[lithium bromate]] at a [[platinum]] [[anode]] gave a yield of about 2% perbromate.<ref name="1st"/> Small amounts of perbromate (1–4% yield) were also formed by the [[xenon difluoride]] oxidation of bromates, while [[perxenate]], [[peroxodisulfate]] and [[ozone]] were ineffective as oxidizing agents.<ref name="1st"/>
 +
 +
==Preparation==
 +
The preparation of macroscopic quantities of perbromates relies on the oxidation of [[sodium bromate]]{{#tag:ref|[[Sodium bromate]] is used as the resulting [[sodium perbromate]] is very soluble in water; [[potassium perbromate]] is much less soluble (as is the case with the corresponding [[perchlorate]]s).<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>|group=note}} in alkaline solution (5&nbsp;M [[sodium hydroxide]]) by gaseous [[fluorine]]:
 +
:BrO{{su|b=3|p=−}} + F<sub>2</sub> + 2 OH<sup>−</sup> &rarr; BrO{{su|b=4|p=−}} + 2 F<sup>−</sup> + H<sub>2</sub>O
 +
The yield is about 20%, and the reaction can be operated on a 100-gram scale. [[Perbromic acid]] can be prepared from the resulting [[sodium perbromate]] by [[ion exchange]], and used to prepare other perbromates.<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>
  
 
==Notes and references==
 
==Notes and references==
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===Further reading===
 
===Further reading===
 +
*{{citation | title = Nonexistent compounds. Two case histories | first = Evan H. | last = Appelman | journal = Acc. Chem. Res. | year = 1973 | volume = 6 | issue = 4 | pages = 113–17 | doi = 10.1021/ar50064a001}}.
 
*{{citation | first1 = Gerald K. | last1 = Johnson | first2 = Peter N. | last2 = Smith | first3 = Evan H. | last3 = Appelman | first4 = Ward N. | last4 = Hubbard | title = Thermodynamic properties of the perbromate and bromate ions | journal = Inorg. Chem. | volume = 9 | issue = 1 | pages = 119–25 | year = 1970 | doi = 10.1021/ic50083a025}}.
 
*{{citation | first1 = Gerald K. | last1 = Johnson | first2 = Peter N. | last2 = Smith | first3 = Evan H. | last3 = Appelman | first4 = Ward N. | last4 = Hubbard | title = Thermodynamic properties of the perbromate and bromate ions | journal = Inorg. Chem. | volume = 9 | issue = 1 | pages = 119–25 | year = 1970 | doi = 10.1021/ic50083a025}}.
 +
*{{citation | title = Heat capacity of potassium perbromate, KBrO<sub>4</sub>, between 5 and 350°K | first1 = Felix | last1 = Schreiner | first2 = Darrell W. | last2 = Osborne | first3 = Alphonsus V. | last3 = Pocius | first4 = Evan H. | last4 = Appelman | journal = Inorg. Chem. | year = 1970 | volume = 9 | issue = 10 | pages = 2320–24 | doi = 10.1021/ic50092a024}}.
 
*{{citation | first1 = Ulrik K. | last1 = Klaening | first2 = Kjeld J. | last2 = Olsen | first3 = Evan H. | last3 = Appelman | title = Photolysis of perbromate in aqueous solution | journal = J. Chem. Soc., Faraday Trans. 1 | volume = 71 | pages = 473–84 | year = 1975 | doi = 10.1039/F19757100473}}.
 
*{{citation | first1 = Ulrik K. | last1 = Klaening | first2 = Kjeld J. | last2 = Olsen | first3 = Evan H. | last3 = Appelman | title = Photolysis of perbromate in aqueous solution | journal = J. Chem. Soc., Faraday Trans. 1 | volume = 71 | pages = 473–84 | year = 1975 | doi = 10.1039/F19757100473}}.
 
*{{citation | first1 = K. J. | last1 = Olsen | first2 = K. | last2 = Sehested | first3 = E. H. | last3 = Appelman | title = Pulse-radiolysis of aqueous KBrO<sub>4</sub> solutions | journal = Chem. Phys. Lett. | volume = 19 | issue = 2 | pages = 213–14 | year = 1973 | doi = 10.1016/0009-2614(73)85057-2}}.
 
*{{citation | first1 = K. J. | last1 = Olsen | first2 = K. | last2 = Sehested | first3 = E. H. | last3 = Appelman | title = Pulse-radiolysis of aqueous KBrO<sub>4</sub> solutions | journal = Chem. Phys. Lett. | volume = 19 | issue = 2 | pages = 213–14 | year = 1973 | doi = 10.1016/0009-2614(73)85057-2}}.
 
*{{citation | title = Preparation of an alkyl perbromate | first1 = Kurt | last1 = Baum | first2 = Charles D. | last2 = Beard | first3 = Vytautas | last3 = Grakauskas | journal = J. Am. Chem. Soc. | year = 1975 | volume = 97 | issue = 2 | pages = 267–68 | doi = 10.1021/ja00835a005}}. {{citation | inventor1-last = Baum | inventor1-first = Kurt | inventor2-last = Beard | inventor2-first = Charles D. | inventor3-last = Grakaukas | inventor3-first = Vitautas | assignee = U.S. Dept. of the Navy | title = Preparation of alkyl perbromates | country-code = US | patent-number = 4022811 | publication-date = 1977-10-05}}.
 
*{{citation | title = Preparation of an alkyl perbromate | first1 = Kurt | last1 = Baum | first2 = Charles D. | last2 = Beard | first3 = Vytautas | last3 = Grakauskas | journal = J. Am. Chem. Soc. | year = 1975 | volume = 97 | issue = 2 | pages = 267–68 | doi = 10.1021/ja00835a005}}. {{citation | inventor1-last = Baum | inventor1-first = Kurt | inventor2-last = Beard | inventor2-first = Charles D. | inventor3-last = Grakaukas | inventor3-first = Vitautas | assignee = U.S. Dept. of the Navy | title = Preparation of alkyl perbromates | country-code = US | patent-number = 4022811 | publication-date = 1977-10-05}}.
*{{citation | title = Nonexistent compounds. Two case histories | first = Evan H. | last = Appelman | journal = Acc. Chem. Res. | year = 1973 | volume = 6 | issue = 4 | pages = 113–17 | doi = 10.1021/ar50064a001}}.
 
*{{citation | title = Heat capacity of potassium perbromate, KBrO<sub>4</sub>, between 5 and 350°K | first1 = Felix | last1 = Schreiner | first2 = Darrell W. | last2 = Osborne | first3 = Alphonsus V. | last3 = Pocius | first4 = Evan H. | last4 = Appelman | journal = Inorg. Chem. | year = 1970 | volume = 9 | issue = 10 | pages = 2320–24 | doi = 10.1021/ic50092a024}}.
 
*{{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}}.
 
  
 
==External links==
 
==External links==

Revision as of 08:01, 5 January 2011

Perbromate
Other names Tetraoxidobromate(1−)
Identifiers
InChI InChI=1/BrHO4/c2-1(3,4)5/h(H,2,3,4,5)/p-1
InChIKey LLYCMZGLHLKPPU-REWHXWOFAT
Standard InChI InChI=1S/BrHO4/c2-1(3,4)5/h(H,2,3,4,5)/p-1
Standard InChIKey LLYCMZGLHLKPPU-UHFFFAOYSA-M
CAS number [16474-32-1]
ChemSpider 4574125
Structure[1]
Molecular geometry r(Br–O) = 161 pm
Related compounds
Other anions Perchlorate
Periodate
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)

A perbromate is a salt or ester of perbromic acid. Perbromates, including perbromic acid,[note 1] are the only well-characterized compounds of bromine in the +7 oxidation state.

Perbromates are thermodynamically more oxidizing than perchlorates or periodates, and eluded preparation for more than 100 years until 1968.[2][3][4] However, they are kinetically quite inert, especially in dilute solution.[3][4][5]

History

Although perchlorates and periodates have been known since the early nineteenth century, perbromates proved far more elusive. The first claim of preparation came in 1863,[6] but proved unrepeatable.[7][8] Several later attempts to prepare perbromates were equally unsuccessful.[9][10] Some authors surmised that perbromates were fundamentally unstable.[11][12]

The first clear evidence of the existence of the perbromate anion came from "hot-atom" techniques. A sample of the β-emittor selenium-83 (t½ = 25 min) was prepared in the form of the selenate anion SeO4 and allowed to decay into bromine-83. Approximately 14% of the 83Br activity (β, t½ = 2.4 h) coprecipitated with rubidium perchlorate, as expected for a perbromate species.[2]

Electrolysis of lithium bromate at a platinum anode gave a yield of about 2% perbromate.[2] Small amounts of perbromate (1–4% yield) were also formed by the xenon difluoride oxidation of bromates, while perxenate, peroxodisulfate and ozone were ineffective as oxidizing agents.[2]

Preparation

The preparation of macroscopic quantities of perbromates relies on the oxidation of sodium bromate[note 2] in alkaline solution (5 M sodium hydroxide) by gaseous fluorine:

BrO3 + F2 + 2 OH → BrO4 + 2 F + H2O

The yield is about 20%, and the reaction can be operated on a 100-gram scale. Perbromic acid can be prepared from the resulting sodium perbromate by ion exchange, and used to prepare other perbromates.[14]

Notes and references

Notes

  1. Perbromic acid is fully dissociated in solution. By analogy with perchloric acid, the solid HBrO4·2H2O is expected to contain [(H2O)2H]+[BrO4].
  2. Sodium bromate is used as the resulting sodium perbromate is very soluble in water; potassium perbromate is much less soluble (as is the case with the corresponding perchlorates).[13]

References

  1. Levason, William; Ogden, J. Steven; Spicer, Mark D.; Young, Nigel A. Characterisation of the oxo-anions of bromine BrOx (x = 1–4) by infrared, Raman, nuclear magnetic resonance, and bromine K-edge extended X-ray absorption fine structure techniques. J. Chem. Soc., Dalton Trans. 1990 (1), 349–53. DOI: 10.1039/DT9900000349.
  2. 2.0 2.1 2.2 2.3 Appelman, Evan H. The Synthesis of Perbromates. J. Am. Chem. Soc. 1968, 90 (7), 1900–1. DOI: 10.1021/ja01009a040. Appelman, Evan H. Perbromic acid and perbromates: synthesis and some properties. Inorg. Chem. 1969, 8 (2), 223–27. DOI: 10.1021/ic50072a008.
  3. 3.0 3.1 Greenwood, Norman N.; Earnshaw, A. Chemistry of the Elements; Pergamon: Oxford, 1984; pp 1020–22. ISBN 0-08-022057-6.
  4. 4.0 4.1 Cotton, F. Albert; Wilkinson, Geoffrey Advanced Inorganic Chemistry, 5th ed.; Wiley-Interscience: New York, 1988; pp 568–69. ISBN 0-471-84997-9.
  5. Kjaer, A. M.; Ulstrup, J. Electron-transfer reactions between the perbromate ion and iron(II) complexes of 2,2'-bipyridine and substituted 1,10-phenanthrolines. Inorg. Chem. 1982, 21 (9), 3490–94. DOI: 10.1021/ic00139a044.
  6. Kämmerer, Hermann Notizen. J. Prakt. Chem. 1863, 90, 190. DOI: 10.1002/prac.18630900126. Kaemmerer, Hermann Studien über die Sauerstoffverbindungen der Halogene. Ann. Phys. (Berlin) 1869, 214 (11), 390–417. DOI: 10.1002/andp.18692141104.
  7. Pattison Muir, M. M. Note on the perbromates. J. Chem. Soc. 1876, 30, 469. DOI: 10.1039/JS8763000469.
  8. Wolfram, Guido Ueber die Darstellung der Perbromsäure. Justus Liebigs Ann. Chem. 1879, 198 (1–2), 95–98. DOI: 10.1002/jlac.18791980107.
  9. Cook, Ernest H. Effect of heat on iodates and bromates. I. Potassic iodate and bromate. J. Chem. Soc., Trans. 1894, 65, 802–14. DOI: 10.1039/CT8946500802.
  10. Bancroft, G. M.; Gesser, H. D. The search for perbromate—I: The thermal decomposition of bromates. J. Inorg. Nucl. Chem. 1965, 27 (7), 1545–56. DOI: 10.1016/0022-1902(65)80016-1.
  11. Hugus, Z. Z., Jr. The Possible Use of 4f Orbitals in Bonding: the Enhanced Stability of the Higher Oxidation States of Iodine, Tellurium and Antimony; the Non-existence of Perbromic Acid. J. Am. Chem. Soc. 1952, 74 (4), 1076–77. DOI: 10.1021/ja01124a502.
  12. Urch, D. S. The perbromate problem. J. Inorg. Nucl. Chem. 1963, 25 (7), 771–78. DOI: 10.1016/0022-1902(63)80360-7.
  13. 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.
  14. Appelman, E. H. Perbromic acid and potassium perbromate. Inorg. Synth. 1972, 13, 1–9. DOI: 10.1002/9780470132449.ch1.

Further reading

External links

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