Difference between revisions of "Chromium(VI) oxide peroxide"

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'''Chromium(VI) oxide peroxide''', also known as '''chromium(VI) peroxide''' or '''chromium(VI) pentoxide''' ('''CrO<sub>5</sub>''') is an unstable compound formed by the addition of an acidified [[hydrogen peroxide]] solution to solutions of metal chromates, such as sodium or [[potassium chromate]], and followed by extraction from aqueous solution with an organic solvent, such as [[diethyl ether]].  
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'''Chromium(VI) oxide peroxide''', also known as '''chromium(VI) peroxide''' or '''chromium pentoxide''' ('''CrO<sub>5</sub>''') is an unstable compound formed by the addition of an acidified [[hydrogen peroxide]] solution to solutions of metal chromates, such as sodium or [[potassium chromate]], and followed by extraction from aqueous solution with an organic solvent, such as [[diethyl ether]].  
  
 
==Properties==
 
==Properties==
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It can be stabilized by the addition of an solvent immiscible with water, such as [[diethyl ether]], [[ethyl acetate]], during the addition of the hydrogen peroxide.
 
It can be stabilized by the addition of an solvent immiscible with water, such as [[diethyl ether]], [[ethyl acetate]], during the addition of the hydrogen peroxide.
  
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Chromium peroxide will form a complex with [[pyridine]].
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Chromium peroxide will form a complex with [[pyridine]] and bipyridine, which is one of the few ways of stabilizing the compound.
  
 
===Physical===
 
===Physical===
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[[Diethyl ether]] or [[ethyl acetate]] is added to stabilize the product.<ref>https://www.youtube.com/watch?v=MjDgXQb4_DU</ref>
 
[[Diethyl ether]] or [[ethyl acetate]] is added to stabilize the product.<ref>https://www.youtube.com/watch?v=MjDgXQb4_DU</ref>
  
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The dissolution of [[chromium trioxide]] on ice is followed by the addition of cooled diethyl ether and finally cooled hydrogen peroxide (at 0 °C) is added. The solution is shaken and the water layer frozen on an ice bath.<ref>Wiede, O. F.; Ber.; vol. 31; (1898); p. 516 - 524</ref>
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The dissolution of [[chromium trioxide]] in crushed ice, followed by the addition of cooled diethyl ether and finally cooled hydrogen peroxide (at 0 °C) is added. The solution is shaken and the water layer frozen on an ice bath.<ref>Wiede, O. F.; Ber.; vol. 31; (1898); p. 516 - 524</ref>
  
 
[[Potassium peroxochromate]] can also be used instead of [[potassium chromate]].<ref>Byers, H. G.; Reid, E. E.; American Chemical Journal; vol. 32; (1904); p. 503 - 513</ref>
 
[[Potassium peroxochromate]] can also be used instead of [[potassium chromate]].<ref>Byers, H. G.; Reid, E. E.; American Chemical Journal; vol. 32; (1904); p. 503 - 513</ref>
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<references/>
 
<references/>
 
===Relevant Sciencemadness threads===
 
===Relevant Sciencemadness threads===
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*[http://www.sciencemadness.org/talk/viewthread.php?tid=157749 Chromium pentoxide uses]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=14911 Lime green solution...]
 
*[http://www.sciencemadness.org/talk/viewthread.php?tid=14911 Lime green solution...]
  

Revision as of 19:51, 12 September 2021

Chromium(VI) oxide peroxide
Names
IUPAC name
Chromium(VI) oxide peroxide
Other names
Chromium(VI) pentoxide
Chromium(VI) peroxide
Chromium oxide peroxide
Chromium pentoxide
Identifiers
Jmol-3D images Image
Properties
CrO5
Molar mass 131.99 g/mol
Appearance Deep blue (solution only)
Odor Odorless
Melting point Decomposes
Boiling point Decomposes
Soluble, but rapidly decomposes
Solubility Soluble in diethyl ether, ethyl acetate, amyl alcohol and its esters, valeric ether
Insoluble in benzene, carbon disulfide, toluene
Hazards
Safety data sheet None
Related compounds
Related compounds
 Chromium trioxide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Chromium(VI) oxide peroxide, also known as chromium(VI) peroxide or chromium pentoxide (CrO5) is an unstable compound formed by the addition of an acidified hydrogen peroxide solution to solutions of metal chromates, such as sodium or potassium chromate, and followed by extraction from aqueous solution with an organic solvent, such as diethyl ether.

Properties

Chemical

Chromium(VI) peroxide is not very stable in water, and will rapidly decompose to Cr(III) ions, releasing oxygen.

2 CrO5 + 7 H2O2 + 6 H+ → 2 Cr3+ + 10 H2O + 7 O2

It can be stabilized by the addition of an solvent immiscible with water, such as diethyl ether, ethyl acetate, during the addition of the hydrogen peroxide.

Chromium peroxide will form a complex with pyridine and bipyridine, which is one of the few ways of stabilizing the compound.

Physical

Chromium(VI) oxide peroxide is a very unstable deep blue compound. It is soluble in water, but rapidly breaks down, and soluble as well as stable in solvents such as diethyl ether, ethyl acetate, amyl alcohol and its esters (formiate, acetate, butyrate, valerate), amyl chloride, valeric ether. It is insoluble in many other solvents, such as aniline, benzene, bergamot oil, CCl4, CS2, castor oil, kerosene, ligroin, nitrobenzene, paraffins, terpene alcohols, toluene, wintergreen oil.[1]

Availability

Chromium peroxide is not sold by any entity due to its instability and has to be made in situ.

Preparation

The addition of an acidified solution of 3% hydrogen peroxide to sodium chromate will cause it to turn from yellow to dark blue-brown. The chromate salt reacts with hydrogen peroxide and an acid to give chromium peroxide, water, and the metal salt of the acid.

Na2CrO4 + 2 H2O2 + 2 H+ → CrO5 + 3 H2O + 2 Na+

Diethyl ether or ethyl acetate is added to stabilize the product.[2]

The dissolution of chromium trioxide in crushed ice, followed by the addition of cooled diethyl ether and finally cooled hydrogen peroxide (at 0 °C) is added. The solution is shaken and the water layer frozen on an ice bath.[3]

Potassium peroxochromate can also be used instead of potassium chromate.[4]

Projects

Handling

Safety

Chromium(V) oxide peroxide is a strong oxidizer, but it's generally too unstable to pose any serious risk. However, if produced in high quantity, it may spontaneously explode.

Storage

Chromium(V) oxide peroxide cannot be stored, as it rapidly decomposes.

Disposal

Since it quickly breaks down to Cr(III) in water, it can be simply poured down the drain. Though it's best to decompose it first, for safety reasons.

References

  1. ↑ Journal of the American Chemical Society; vol. 17; (1895); p. 41 - 43
  2. ↑ https://www.youtube.com/watch?v=MjDgXQb4_DU
  3. ↑ Wiede, O. F.; Ber.; vol. 31; (1898); p. 516 - 524
  4. ↑ Byers, H. G.; Reid, E. E.; American Chemical Journal; vol. 32; (1904); p. 503 - 513

Relevant Sciencemadness threads

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