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{{short description|Trivalent anion}}

In [[chemistry]], '''hypomanganate''', also called '''manganate(V)''' or '''tetraoxidomanganate(3−)''', is a [[trivalent]] [[anion]] ([[electric charge|negative]] [[ion]]) composed of [[manganese]] and [[oxygen]], with formula {{chem|MnO|4|3-}}.
In [[chemistry]], '''hypomanganate''', also called '''manganate(V)''' or '''tetraoxidomanganate(3−)''', is a [[trivalent]] [[anion]] ([[electric charge|negative]] [[ion]]) composed of [[manganese]] and [[oxygen]], with formula {{chem|MnO|4|3-}}.


Hypomanganates are usually bright blue.<ref name="G&E"/><ref name=Reinen>D. Reinen, W. Rauw, U. Kesper, M. Atanasov, H. U Güdel, M. Hazenkamp, and U. Oetliker (1997): "Colour, luminescence and bonding properties of tetrahedrally coordinated chromium(IV), manganese(V) and iron(VI) in various oxide ceramics" ''Journal of Alloys and Compounds'', volume 246, issue 1-2, pages 193-208. {{doi|10.1016/S0925-8388(96)02461-9}}</ref> [[Potassium hypomanganate]] {{chem|K|3|MnO|4}} is the best known [[salt (chemistry)|salt]], but [[sodium hypomanganate]] {{chem|Na|3|MnO|4|}}, [[barium hypomanganate]] {{chem|Ba|3|(|MnO|4|)|2}}, and the mixed potassium-barium salt {{chem|KBaMnO|4}} is also known.<ref name=Loye/> The anion can replace [[phosphate]] {{chem|PO|4|3-}} in synthetic variants of the minerals [[apatite]]<ref name=Dardenne>K. Dardenne, D. Vivien, and D. Huguenin (1999): "Color of Mn(V)-substituted apatites A<sub>10</sub>((B, Mn)O<sub>4</sub>)<sub>6</sub>F<sub>2</sub>, A = Ba, Sr, Ca; B= P, V". ''Journal of Solid State Chem.istry, volume 146, issue 2, pages 464-472. {{doi|10.1006/jssc.1999.8394}}</ref><ref name=Grisafe> Grisafe, D.A. and Hummel, F.A. (1970): "Pentavalent ion substitutions in the apatite structure, part A: Crystal chemistry". ''Journal of Solid State Chemistry'', volume 2, issue 2, pages 160-166 {{doi|10.1016/0022-4596(70)90064-2}}</ref> and [[brownmillerite]].<ref name=Jiang>P. Jiang, J. Li, A. Ozarowski, A. W. Sleight, and M. A, Subramanian (2013): "Intense turquoise and green colors in brownmillerite-type oxides based on Mn<sup>5+</sup> in {{chem|Ba|2|In|2-''x''|Mn|''x''|O|5+''x''}}" ''Inorganic Chemistry'', volume 52, issue 3, pages 1349-1357. {{doi|10.1021/ic3020332}}</ref>
Hypomanganates are usually bright blue.<ref name="G&E"/><ref name=Reinen>D. Reinen, W. Rauw, U. Kesper, M. Atanasov, H. U Güdel, M. Hazenkamp, and U. Oetliker (1997): "Colour, luminescence and bonding properties of tetrahedrally coordinated chromium(IV), manganese(V) and iron(VI) in various oxide ceramics" ''Journal of Alloys and Compounds'', volume 246, issue 1-2, pages 193-208. {{doi|10.1016/S0925-8388(96)02461-9}}</ref> [[Potassium hypomanganate]] {{chem|K|3|MnO|4}} is the best known [[salt (chemistry)|salt]], but [[sodium hypomanganate]] {{chem|Na|3|MnO|4|}}, [[barium hypomanganate]] {{chem|Ba|3|(|MnO|4|)|2}}, and the mixed potassium-barium salt {{chem|KBaMnO|4}} is also known.<ref name=Loye/> The anion can replace [[phosphate]] {{chem|PO|4|3-}} in synthetic variants of the minerals [[apatite]]<ref name=Dardenne>K. Dardenne, D. Vivien, and D. Huguenin (1999): "Color of Mn(V)-substituted apatites A<sub>10</sub>((B, Mn)O<sub>4</sub>)<sub>6</sub>F<sub>2</sub>, A = Ba, Sr, Ca; B= P, V". ''Journal of Solid State Chem.istry'', volume 146, issue 2, pages 464-472. {{doi|10.1006/jssc.1999.8394}}</ref><ref name=Grisafe> Grisafe, D.A. and Hummel, F.A. (1970): "Pentavalent ion substitutions in the apatite structure, part A: Crystal chemistry". ''Journal of Solid State Chemistry'', volume 2, issue 2, pages 160-166 {{doi|10.1016/0022-4596(70)90064-2}}</ref> and [[brownmillerite]].<ref name=Jiang>P. Jiang, J. Li, A. Ozarowski, A. W. Sleight, and M. A, Subramanian (2013): "Intense turquoise and green colors in brownmillerite-type oxides based on Mn<sup>5+</sup> in {{chem|Ba|2|In|2-''x''|Mn|''x''|O|5+''x''}}" ''Inorganic Chemistry'', volume 52, issue 3, pages 1349-1357. {{doi|10.1021/ic3020332}}</ref>


==History==
==History==
Line 7: Line 9:


==Structure and properties==
==Structure and properties==
Manganate(V) is a tetrahedral [[oxyanion]] structurally similar to [[sulfate]], manganate, and permanganate. As expected for a tetrahedral complex with a d<sup>2</sup> configuration, the anion has a [[triplet state|triplet]] ground state.<ref name=Loye>{{cite journal|authors=zur Loye, K. D.; Chance, W. M.; Yeon, J.; zur Loye, H.-C.|title=Synthesis, Crystal Structure, and Magnetic Properties of the Oxometallates KBaMnO<sub>4</sub> and KBaAsO<sub>4</sub>|journal=Solid State Sciences|year=2014|volume=37|pages=86-90|doi=10.1016/j.solidstatesciences.2014.08.013}}</ref>
Manganate(V) is a tetrahedral [[oxyanion]] structurally similar to [[sulfate]], manganate, and permanganate. As expected for a tetrahedral complex with a d<sup>2</sup> configuration, the anion has a [[triplet state|triplet]] ground state.<ref name=Loye>{{cite journal|author1=zur Loye, K. D. |author2=Chance, W. M. |author3=Yeon, J. |author4=zur Loye, H.-C. |title=Synthesis, Crystal Structure, and Magnetic Properties of the Oxometallates KBaMnO<sub>4</sub> and KBaAsO<sub>4</sub>|journal=Solid State Sciences|year=2014|volume=37|pages=86–90|doi=10.1016/j.solidstatesciences.2014.08.013|bibcode=2014SSSci..37...86Z|doi-access=free}}</ref>


The anion is a bright blue species<ref name="G&E">{{Greenwood&Earnshaw1st|pages=1221–22}}.</ref> with a visible absorption maximum at wavelength ''λ''<sub>max</sub>&nbsp;= 670&nbsp;nm (''ε'' = {{nowrap|900&nbsp;dm<sup>3</sup> mol<sup>−1</sup> cm<sup>−1</sup>}}).<ref name="JCS">{{citation | journal = J. Chem. Soc. | year = 1956 | pages = 3373–80 | doi = 10.1039/JR9560003373 | title = Structure and reactivity of the oxy-anions of transition metals. Part I. The manganese oxy-anions | first1 = A. | last1 = Carrington | first2 = M. C. R. | last2 = Symons}}</ref><ref name="Mandelate">{{citation | title = Reduction of manganate(VI) by mandelic acid and its significance for development of a general mechanism of oxidation of organic compounds by high-valent transition metal oxides | first1 = Donald G. | last1 = Lee | first2 = Tao | last2 = Chen | journal = J. Am. Chem. Soc. | year = 1993 | volume = 115 | issue = 24 | pages = 11231–36 | doi = 10.1021/ja00077a023}}.</ref>
The anion is a bright blue species<ref name="G&E">{{Greenwood&Earnshaw1st|pages=1221–22}}.</ref> with a visible absorption maximum at wavelength ''λ''<sub>max</sub>&nbsp;= 670&nbsp;nm (''ε'' = {{nowrap|900&nbsp;dm<sup>3</sup> mol<sup>−1</sup> cm<sup>−1</sup>}}).<ref name="JCS">{{citation | journal = J. Chem. Soc. | year = 1956 | pages = 3373–80 | doi = 10.1039/JR9560003373 | title = Structure and reactivity of the oxy-anions of transition metals. Part I. The manganese oxy-anions | first1 = A. | last1 = Carrington | first2 = M. C. R. | last2 = Symons}}</ref><ref name="Mandelate">{{citation | title = Reduction of manganate(VI) by mandelic acid and its significance for development of a general mechanism of oxidation of organic compounds by high-valent transition metal oxides | first1 = Donald G. | last1 = Lee | first2 = Tao | last2 = Chen | journal = J. Am. Chem. Soc. | year = 1993 | volume = 115 | issue = 24 | pages = 11231–36 | doi = 10.1021/ja00077a023}}.</ref>
Line 15: Line 17:
:MnO{{su|b=4|p=2−}} + e<sup>−</sup> {{eqm}} MnO{{su|b=4|p=3−}}&nbsp;&nbsp;&nbsp;''E'' = +0.27 V
:MnO{{su|b=4|p=2−}} + e<sup>−</sup> {{eqm}} MnO{{su|b=4|p=3−}}&nbsp;&nbsp;&nbsp;''E'' = +0.27 V
:MnO{{su|b=4|p=3−}} + e<sup>−</sup> + {{nowrap|2 H<sub>2</sub>O}} {{eqm}} MnO<sub>2</sub> + {{nowrap|4 OH<sup>−</sup>}}&nbsp;&nbsp;&nbsp;''E'' = +0.96 V
:MnO{{su|b=4|p=3−}} + e<sup>−</sup> + {{nowrap|2 H<sub>2</sub>O}} {{eqm}} MnO<sub>2</sub> + {{nowrap|4 OH<sup>−</sup>}}&nbsp;&nbsp;&nbsp;''E'' = +0.96 V
However, the reaction is slow in very alkaline solutions (with OH<sup>−</sup> concentration above 5–10 [[mole (unit)|mol]]/[[liter|L]].<ref name="G&E"/><ref name=Lux/>
However, the reaction is slow in very alkaline solutions (with OH<sup>−</sup> concentration above 5–10 [[mole (unit)|mol]]/[[liter|L]]).<ref name="G&E"/><ref name=Lux/>


The disproportionation is believed to pass through a protonated intermediate,<ref name="Epot"/> with the [[acid dissociation constant]] for the reaction HMnO{{su|b=4|p=2−}}&nbsp;{{eqm}} MnO{{su|b=4|p=3−}}&nbsp;+ H<sup>+</sup> being estimated as p''K''<sub>a</sub>&nbsp;= {{nowrap|13.7 ± 0.2}}.<ref name=PulseRad>{{citation | title = Studies of Manganate(V), -(VI), and -(VII) Tetraoxyanions by Pulse Radiolysis. Optical Spectra of Protonated Forms | first1 = J. D. | last1 = Rush | first2 = B. H. J. | last2 = Bielski | journal = Inorg. Chem. | year = 1995 | volume = 34 | issue = 23 | pages = 5832–38 | doi = 10.1021/ic00127a022}}.</ref> However, K<sub>3</sub>MnO<sub>4</sub> has been cocrystallized with Ca<sub>2</sub>Cl(PO<sub>4</sub>), allowing the study of the [[Ultraviolet–visible spectroscopy|UV–visible spectrum]] of the hypomanganate ion.<ref name="C&W"/><ref>{{citation | journal = J. Chem. Soc. | year = 1956 | pages = 3373–80 | doi = 10.1039/JR9560003373 | title = Structure and reactivity of the oxy-anions of transition metals. Part I. The manganese oxy-anions | first1 = A. | last1 = Carrington | first2 = M. C. R. | last2 = Symons}}.</ref>
The disproportionation is believed to pass through a protonated intermediate,<ref name="Epot"/> with the [[acid dissociation constant]] for the reaction HMnO{{su|b=4|p=2−}}&nbsp;{{eqm}} MnO{{su|b=4|p=3−}}&nbsp;+ H<sup>+</sup> being estimated as p''K''<sub>a</sub>&nbsp;= {{nowrap|13.7 ± 0.2}}.<ref name=PulseRad>{{citation | title = Studies of Manganate(V), -(VI), and -(VII) Tetraoxyanions by Pulse Radiolysis. Optical Spectra of Protonated Forms | first1 = J. D. | last1 = Rush | first2 = B. H. J. | last2 = Bielski | journal = Inorg. Chem. | year = 1995 | volume = 34 | issue = 23 | pages = 5832–38 | doi = 10.1021/ic00127a022}}.</ref> However, K<sub>3</sub>MnO<sub>4</sub> has been cocrystallized with Ca<sub>2</sub>Cl(PO<sub>4</sub>), allowing the study of the [[Ultraviolet–visible spectroscopy|UV–visible spectrum]] of the hypomanganate ion.<ref name="C&W"/><ref>{{citation | journal = J. Chem. Soc. | year = 1956 | pages = 3373–80 | doi = 10.1039/JR9560003373 | title = Structure and reactivity of the oxy-anions of transition metals. Part I. The manganese oxy-anions | first1 = A. | last1 = Carrington | first2 = M. C. R. | last2 = Symons}}.</ref>
Line 22: Line 24:
Hypomanganates may be prepared by the careful reduction of manganates with [[sulfite]],<ref name="G&E"/> [[hydrogen peroxide]]<ref name="H2O2">{{citation | title = Oxidation of hydrocarbons. 18. Mechanism of the reaction between permanganate and carbon-carbon double bonds | first1 = Donald G. | last1 = Lee | first2 = Tao | last2 = Chen | journal = J. Am. Chem. Soc. | year = 1989 | volume = 111 | issue = 19 | pages = 7534–38 | doi = 10.1021/ja00201a039}}.</ref> or [[Mandelic acid|mandelate]].<ref name="Mandelate"/>
Hypomanganates may be prepared by the careful reduction of manganates with [[sulfite]],<ref name="G&E"/> [[hydrogen peroxide]]<ref name="H2O2">{{citation | title = Oxidation of hydrocarbons. 18. Mechanism of the reaction between permanganate and carbon-carbon double bonds | first1 = Donald G. | last1 = Lee | first2 = Tao | last2 = Chen | journal = J. Am. Chem. Soc. | year = 1989 | volume = 111 | issue = 19 | pages = 7534–38 | doi = 10.1021/ja00201a039}}.</ref> or [[Mandelic acid|mandelate]].<ref name="Mandelate"/>


Hypomanganates can also be prepared by the solid state method under O2 flow near 1000 °C<ref name=Loye/><ref name=Dardenne/><ref name=Grisafe/> <ref name=Jiang/> They can be prepared also via low temperature routes such as hydrothermal synthesis or flux growth.<ref name=Loye/>
Hypomanganates can also be prepared by the solid state method under {{O2}} flow near 1000 °C.<ref name=Loye/><ref name=Dardenne/><ref name=Grisafe/> <ref name=Jiang/> They can be prepared also via low temperature routes such as hydrothermal synthesis or flux growth.<ref name=Loye/> It is produced by dissolving manganese dioxide in molten [[sodium nitrite]].<ref>{{cite journal|first=R. B. |last=Temple|author2=Thickett, G. W.|title=The formation of manganese(v) in molten sodium nitrite|journal=Australian Journal of Chemistry|date=1972|volume=25|page=55|doi=10.1071/CH9720655|issue=3|doi-access=free}}</ref>


==Uses==
==Uses==
Line 44: Line 46:
{{reflist}}
{{reflist}}


[[Category:Manganese compounds]]
[[Category:Manganese(V) compounds]]
[[Category:Oxygen compounds]]
[[Category:Transition metal oxyanions]]

Latest revision as of 16:28, 2 July 2024

In chemistry, hypomanganate, also called manganate(V) or tetraoxidomanganate(3−), is a trivalent anion (negative ion) composed of manganese and oxygen, with formula MnO3−
4.

Hypomanganates are usually bright blue.[1][2] Potassium hypomanganate K
3MnO
4 is the best known salt, but sodium hypomanganate Na
3MnO
4, barium hypomanganate Ba
3(MnO
4)
2, and the mixed potassium-barium salt KBaMnO
4 is also known.[3] The anion can replace phosphate PO3−
4 in synthetic variants of the minerals apatite[4][5] and brownmillerite.[6]

History

[edit]

The manganate(V) anion was first reported in 1946 by Hermann Lux, who synthesized the intensely blue sodium hypomanganate by reacting sodium oxide Na
2O and manganese dioxide MnO
2 in fused sodium nitrite NaNO
2 at 500 °C.[7][3] He also crystalized the salt from strong (50%) sodium hydroxide solutions as the decahydrate Na
3MnO
4·10H
2O.

Structure and properties

[edit]

Manganate(V) is a tetrahedral oxyanion structurally similar to sulfate, manganate, and permanganate. As expected for a tetrahedral complex with a d2 configuration, the anion has a triplet ground state.[3]

The anion is a bright blue species[1] with a visible absorption maximum at wavelength λmax = 670 nm (ε = 900 dm3 mol−1 cm−1).[8][9]

Stability

[edit]

Hypomanganate is unstable towards disproportionation to manganate(VI) and manganese dioxide:[10][1] The estimated electrode potentials at pH 14 are:[11][12][13]

MnO2−
4 + e− ⇌ MnO3−
4   E = +0.27 V
MnO3−
4 + e− + 2 H2O ⇌ MnO2 + 4 OH−   E = +0.96 V

However, the reaction is slow in very alkaline solutions (with OH− concentration above 5–10 mol/L).[1][7]

The disproportionation is believed to pass through a protonated intermediate,[13] with the acid dissociation constant for the reaction HMnO2−
4 ⇌ MnO3−
4 + H+ being estimated as pKa = 13.7 ± 0.2.[14] However, K3MnO4 has been cocrystallized with Ca2Cl(PO4), allowing the study of the UV–visible spectrum of the hypomanganate ion.[10][15]

Preparation

[edit]

Hypomanganates may be prepared by the careful reduction of manganates with sulfite,[1] hydrogen peroxide[16] or mandelate.[9]

Hypomanganates can also be prepared by the solid state method under O2 flow near 1000 °C.[3][4][5] [6] They can be prepared also via low temperature routes such as hydrothermal synthesis or flux growth.[3] It is produced by dissolving manganese dioxide in molten sodium nitrite.[17]

Uses

[edit]

The strontium vanadate fluoride Sr
5(VO
4)
3F compound, with hypomanganate substituted for some vanadate units, has been investigated for potential use in near infrared lasers.[18]

The barium salt Ba
3(MnO
4)
2 has interesting magnetic properties.[19]

[edit]

In theory, hypomanganate would be the conjugate base of hypomanganic acid H
3MnO
4. This acid cannot be formed because of its rapid disproportionation, but its third acid dissociation constant has been estimated by pulse radiolysis techniques:[14]

HMnO2−
4 ⇌ MnO3−
4 + H+   pKa = 13.7 ± 0.2

Cyclic esters of hypomanganic acid are thought to be intermediates in the oxidation of alkenes by permanganate.[9]

See also

[edit]

References

[edit]
  1. ^ a b c d e Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. pp. 1221–22. ISBN 978-0-08-022057-4..
  2. ^ D. Reinen, W. Rauw, U. Kesper, M. Atanasov, H. U Güdel, M. Hazenkamp, and U. Oetliker (1997): "Colour, luminescence and bonding properties of tetrahedrally coordinated chromium(IV), manganese(V) and iron(VI) in various oxide ceramics" Journal of Alloys and Compounds, volume 246, issue 1-2, pages 193-208. doi:10.1016/S0925-8388(96)02461-9
  3. ^ a b c d e zur Loye, K. D.; Chance, W. M.; Yeon, J.; zur Loye, H.-C. (2014). "Synthesis, Crystal Structure, and Magnetic Properties of the Oxometallates KBaMnO4 and KBaAsO4". Solid State Sciences. 37: 86–90. Bibcode:2014SSSci..37...86Z. doi:10.1016/j.solidstatesciences.2014.08.013.
  4. ^ a b K. Dardenne, D. Vivien, and D. Huguenin (1999): "Color of Mn(V)-substituted apatites A10((B, Mn)O4)6F2, A = Ba, Sr, Ca; B= P, V". Journal of Solid State Chem.istry, volume 146, issue 2, pages 464-472. doi:10.1006/jssc.1999.8394
  5. ^ a b Grisafe, D.A. and Hummel, F.A. (1970): "Pentavalent ion substitutions in the apatite structure, part A: Crystal chemistry". Journal of Solid State Chemistry, volume 2, issue 2, pages 160-166 doi:10.1016/0022-4596(70)90064-2
  6. ^ a b P. Jiang, J. Li, A. Ozarowski, A. W. Sleight, and M. A, Subramanian (2013): "Intense turquoise and green colors in brownmillerite-type oxides based on Mn5+ in Ba
    2    In
    2-x    Mn
    x    O
    5+x    " Inorganic Chemistry, volume 52, issue 3, pages 1349-1357. doi:10.1021/ic3020332
  7. ^ a b Herrman Lux (1946): "Über Salze des fünfwertigen Mangans." Zeitschrift für Naturforschung, volume 1, pages 281-283.
  8. ^ Carrington, A.; Symons, M. C. R. (1956), "Structure and reactivity of the oxy-anions of transition metals. Part I. The manganese oxy-anions", J. Chem. Soc.: 3373–80, doi:10.1039/JR9560003373
  9. ^ a b c Lee, Donald G.; Chen, Tao (1993), "Reduction of manganate(VI) by mandelic acid and its significance for development of a general mechanism of oxidation of organic compounds by high-valent transition metal oxides", J. Am. Chem. Soc., 115 (24): 11231–36, doi:10.1021/ja00077a023.
  10. ^ a b Cotton, F. Albert; Wilkinson, Geoffrey (1980), Advanced Inorganic Chemistry (4th ed.), New York: Wiley, p. 746, ISBN 0-471-02775-8.
  11. ^ Weast, Robert C., ed. (1981). CRC Handbook of Chemistry and Physics (62nd ed.). Boca Raton, Florida: CRC Press. p. D-134. ISBN 0-8493-0462-8..
  12. ^ Manganese – compounds – standard reduction potentials, WebElements, retrieved 2010-06-26.
  13. ^ a b Sekula-Brzezińska, K.; Wrona, P. K.; Galus, Z. (1979), "Rate of the MnO4−/MnO42− and MnO42−/MnO43− electrode reactions in alkaline solutions at solid electrodes", Electrochim. Acta, 24 (5): 555–63, doi:10.1016/0013-4686(79)85032-X.
  14. ^ a b Rush, J. D.; Bielski, B. H. J. (1995), "Studies of Manganate(V), -(VI), and -(VII) Tetraoxyanions by Pulse Radiolysis. Optical Spectra of Protonated Forms", Inorg. Chem., 34 (23): 5832–38, doi:10.1021/ic00127a022.
  15. ^ Carrington, A.; Symons, M. C. R. (1956), "Structure and reactivity of the oxy-anions of transition metals. Part I. The manganese oxy-anions", J. Chem. Soc.: 3373–80, doi:10.1039/JR9560003373.
  16. ^ Lee, Donald G.; Chen, Tao (1989), "Oxidation of hydrocarbons. 18. Mechanism of the reaction between permanganate and carbon-carbon double bonds", J. Am. Chem. Soc., 111 (19): 7534–38, doi:10.1021/ja00201a039.
  17. ^ Temple, R. B.; Thickett, G. W. (1972). "The formation of manganese(v) in molten sodium nitrite". Australian Journal of Chemistry. 25 (3): 55. doi:10.1071/CH9720655.
  18. ^ L. D. Merkle, Y. Guyot, and B. H. T. Chai (1995): "Spectroscopic and laser investigations of Mn5+:Sr5(VO4)3F". Journal of Applied Physics, volume 77, issue 2, pages 474-480. doi:10.1063/1.359585
  19. ^ M. B. Stone, M. D. Lumsden, Y. Qiu, E. C. Samulon, C. D. Batista, and I. R. Fisher (2008): "Dispersive magnetic excitations in the S=1 antiferromagnet Ba
    3    Mn
    2    O
    8    ". Physics Review B, volume 77, page 134406 doi:10.1103/PhysRevB.77.134406
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