Copper(I) oxide: Difference between revisions
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| Section2 = {{Chembox Properties | | Section2 = {{Chembox Properties | ||
| Formula = | | Formula = {{chem2|Cu2O}} | ||
| MolarMass = 143.09 g/mol | | MolarMass = 143.09 g/mol | ||
| Appearance = yellow, red, or brown solid | | Appearance = yellow, red, or brown solid | ||
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| BoilingPt_notes = ''decomposes'' | | BoilingPt_notes = ''decomposes'' | ||
| BandGap = 2.137 [[Electronvolt|eV]] | | BandGap = 2.137 [[Electronvolt|eV]] | ||
| MagSus = {{val|-20e-6|u= | | MagSus = {{val|-20e-6|u=cm3/mol}}}} | ||
| Section3 = {{Chembox Structure | | Section3 = {{Chembox Structure | ||
| Coordination = | | Coordination = | ||
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| NFPA-F = 0 | | NFPA-F = 0 | ||
| NFPA-R = 1 | | NFPA-R = 1 | ||
| PEL = TWA 1 mg/ | | PEL = TWA {{val|1|u=mg/m3}} (as Cu)<ref name=PGCH>{{PGCH|0150}}</ref> | ||
| REL = TWA 1 mg/ | | REL = TWA {{val|1|u=mg/m3}}(as Cu)<ref name=PGCH/> | ||
| IDLH = TWA 100 mg/ | | IDLH = TWA {{val|100|u=mg/m3}} (as Cu)<ref name=PGCH/> | ||
}} | }} | ||
| Section8 = {{Chembox Related | | Section8 = {{Chembox Related | ||
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'''Copper(I) oxide''' or '''cuprous oxide''' is the [[inorganic compound]] with the formula | '''Copper(I) oxide''' or '''cuprous oxide''' is the [[inorganic compound]] with the formula {{chem2|Cu2O}}. It is one of the principal [[oxide]]s of [[copper]], the other being [[copper(II) oxide]] or cupric oxide (CuO). The compound can appear either yellow or red,<ref>{{cite book |last1=Greenwood |first1=N. N. |last2=Earnshaw |first2=A. |title=Chemistry of the elements |date=1997 |publisher=Butterworth-Heinemann |location=Oxford; Boston |isbn=0750633654 |edition=2nd |chapter=Compounds of Copper, Silver and Gold |page=1181 |url=https://tech.chemistrydocs.com/Books/General%20Chemistry/Chemistry-of-the-Element-by-N.-N.-Greenwood.pdf?page=1214}}</ref> depending on the size of the particles.<ref name=Brauer>{{cite book|author1=O. Glemser|author2=R. Sauer|chapter=Copper (I) Oxide|title=Handbook of Preparative Inorganic Chemistry, 2nd Ed. |editor=G. Brauer|publisher=Academic Press|year=1963|place=NY, NY|volume=2|page=1011 |url=https://archive.org/details/Handbook_of_Preparative_Inorganic_Chemistry_1_2_Brauer/page/n1057/mode/2up |ISBN=978-0121266011}}</ref> Cuprous oxide is found as the [[mineral]] [[cuprite]]. | ||
It is a component of some [[antifouling]] paints, and has other applications including some that exploit its property as a [[semiconductor]]. | |||
==Preparation== | ==Preparation== | ||
Copper(I) oxide may be produced by several methods.<ref name=Ullmann/> Most straightforwardly, it arises via the [[Redox|oxidation]] of copper metal: | Copper(I) oxide may be produced by several methods.<ref name=Ullmann/> Most straightforwardly, it arises via the [[Redox|oxidation]] of copper metal: | ||
: {{chem2|4 Cu | : {{chem2|4 Cu + O2 -> 2 Cu2O}} | ||
Additives such as water and acids affect the rate as well as the further oxidation to copper(II) oxides. It is also produced commercially by reduction of copper(II) solutions with [[sulfur dioxide]]. | Additives such as water and acids affect the rate as well as the further oxidation to copper(II) oxides. It is also produced commercially by reduction of copper(II) solutions with [[sulfur dioxide]]. | ||
Alternatively, it may be prepared via the reduction of [[copper(II) acetate]] with [[hydrazine]]:<ref | Alternatively, it may be prepared via the reduction of [[copper(II) acetate]] with [[hydrazine]]:<ref name=Brauer /> | ||
:{{chem2|4 Cu(O2CCH3)2 | :{{chem2|4 Cu(O2CCH3)2 + N2H4 + 2 H2O -> 2 Cu2O + 8 CH3CO2H + N2}} | ||
Copper(I) chloride solutions react with base to give the same material. In all cases, the color of the cuprous oxide is highly sensitive to the procedural details. {{chem2|Cu2O}} degrades to copper(II) oxide in moist air. | |||
[[File:Cu-pourbaix-diagram.svg|thumbnail|left|[[Pourbaix diagram]] for copper in uncomplexed media (anions other than | [[File:Cu-pourbaix-diagram.svg|thumbnail|left|[[Pourbaix diagram]] for copper in uncomplexed media (anions other than {{chem2|OH−}} not considered). Ion concentration {{val|0.001|u=mol/kg}} water. Temperature {{convert|25|C|F}}.]] | ||
Formation of copper(I) oxide is the basis of the [[Fehling's solution|Fehling's test]] and [[Benedict's reagent|Benedict's test]] for reducing [[sugar]]s. These sugars reduce an [[alkaline]] solution of a copper(II) salt, giving a bright red [[precipitate]] of | Formation of copper(I) oxide is the basis of the [[Fehling's solution|Fehling's test]] and [[Benedict's reagent|Benedict's test]] for reducing [[sugar]]s. These sugars reduce an [[alkaline]] solution of a copper(II) salt, giving a bright red [[precipitate]] of {{chem2|Cu2O}}. | ||
It forms on [[silver]]-plated copper parts exposed to moisture when the silver layer is porous or damaged. This kind of [[corrosion]] is known as [[red plague (corrosion)|red plague]]. | It forms on [[silver]]-plated copper parts exposed to moisture when the silver layer is porous or damaged. This kind of [[corrosion]] is known as [[red plague (corrosion)|red plague]]. | ||
| Line 103: | Line 103: | ||
Like all copper(I) compounds, cuprous oxide is [[diamagnetic]]. It does not readily hydrate to [[cuprous hydroxide]]. | Like all copper(I) compounds, cuprous oxide is [[diamagnetic]]. It does not readily hydrate to [[cuprous hydroxide]]. | ||
Copper(I) oxide dissolves in concentrated [[ammonia]] solution to form the colourless [[complex (chemistry)|complex]] [Cu( | Copper(I) oxide dissolves in concentrated [[ammonia]] solution to form the colourless [[complex (chemistry)|complex]] {{chem2|[Cu(NH3)2]+}}, which is easily [[redox|oxidized]] in air to the blue {{chem2|[Cu(NH3)4(H2O)2]^{2+} }}. | ||
Cuprous oxide is attacked by acids. [[Hydrochloric acid]] gives the [[chloride complex]] {{ | Cuprous oxide is attacked by acids. [[Hydrochloric acid]] gives the [[chloride complex]] {{chem2|CuCl2-}}. [[Sulfuric acid]] and [[nitric acid]] produce [[copper(II) sulfate]] and [[copper(II) nitrate]], respectively.<ref>{{cite book |last1=Nicholls |first1=David |title=Complexes and first-row transition elements |date=1973 |publisher=Macmillan Education Ltd. |location=Houndmills, Basingstoke, Hampshire, and London |isbn=0333170881 |edition=Repr}}</ref>{{page needed|date=June 2025}} | ||
== Structure == | == Structure == | ||
{{unreferenced section|date=June 2025}} | |||
[[Image:Cuprite-66649.jpg|thumb|left|110px|Large crystal of the mineral form of copper(I) oxide ([[cuprite]]).]] | [[Image:Cuprite-66649.jpg|thumb|left|110px|Large crystal of the mineral form of copper(I) oxide ([[cuprite]]).]] | ||
In terms of their coordination spheres, copper centres are 2-coordinated and the oxides are [[Tetrahedral molecular geometry|tetrahedral]]. The structure thus resembles in some sense the main [[Silicon dioxide#Crystalline forms|polymorphs of | In terms of their coordination spheres, copper centres are 2-coordinated and the oxides are [[Tetrahedral molecular geometry|tetrahedral]]. The structure thus resembles in some sense the main [[Silicon dioxide#Crystalline forms|polymorphs of {{chem2|SiO2}}]], but cuprous oxide's lattices interpenetrate. {{chem2|Cu2O}} crystallizes in a [[Cubic crystal system|cubic]] structure with a lattice constant ''a''<sub>l</sub> = {{val|4.2696|u=Å}}. The copper atoms arrange in a [[Bravais lattice]] fcc sublattice, the oxygen atoms in a bcc sublattice. One sublattice is shifted by a quarter of the body diagonal. The [[space group]] is Pn{{overline|3}}m, which includes the [[point group]] with full octahedral symmetry. | ||
==Applications== | ==Applications== | ||
The dominant use of cuprous oxide is as a component of [[antifouling]] paints.<ref name=Ullmann>{{cite book |doi=10.1002/14356007.a07_567.pub2 |chapter=Copper Compounds |title=Ullmann's Encyclopedia of Industrial Chemistry |date=2016 |last1=Zhang |first1=Jun |last2=Richardson |first2=H. Wayne |pages=1–31 |isbn=978-3-527-30673-2 }}</ref> | The dominant use of cuprous oxide is as a component of [[antifouling]] paints.<ref name=Ullmann>{{cite book |doi=10.1002/14356007.a07_567.pub2 |chapter=Copper Compounds |title=Ullmann's Encyclopedia of Industrial Chemistry |date=2016 |last1=Zhang |first1=Jun |last2=Richardson |first2=H. Wayne |pages=1–31 |isbn=978-3-527-30673-2 }}</ref> | ||
Cuprous oxide is also commonly used as a [[pigment]] and a [[fungicide]]. | Cuprous oxide is also commonly used as a [[pigment]] and a [[fungicide]].{{citation needed|date=June 2025}} | ||
===Semiconductor and related uses=== | ===Semiconductor and related uses=== | ||
[[Rectifier|Rectifier diode]]s based on this material have been used industrially as early as 1924, long before [[silicon]] became the standard. Copper(I) oxide is also responsible for the pink color in a positive [[Benedict's reagent|Benedict's test]]. | [[Rectifier|Rectifier diode]]s based on this material have been used industrially as early as 1924, long before [[silicon]] became the standard. Copper(I) oxide is also responsible for the pink color in a positive [[Benedict's reagent|Benedict's test]]. | ||
In the history of [[semiconductor]] physics, Cu<sub>2</sub>O is one of the most studied materials. Many | In the history of [[semiconductor]] physics, Cu<sub>2</sub>O is one of the most studied materials. Many applications have been demonstrated first in this material: | ||
*Semiconductor [[diode]]s<ref> | *Semiconductor [[diode]]s<ref>{{cite patent |title=Unidirectional current-carrying device |number=US1640335A |country=US |inventor=Lars O Grondahl |status=Expired - Lifetime |pubdate=1927-08-23 |fdate=1925-01-07 |gdate=1927-08-23 |pridate=1927-07-28 |assign1=Hitachi Rail STS USA Inc }}</ref> | ||
*Phonoritons ("a coherent superposition of [[exciton]], [[photon]], and [[phonon]]")<ref>{{Cite journal|last1=Hanke|first1=L.|last2=Fröhlich|first2=D.|last3=Ivanov|first3=A. L.|last4=Littlewood|first4=P. B.|last5=Stolz|first5=H.|date=1999-11-22|title=LA Phonoritons in Cu | *Phonoritons ("a coherent superposition of [[exciton]], [[photon]], and [[phonon]]")<ref>{{Cite journal |last1=Hanke |first1=L. |last2=Fröhlich |first2=D. |last3=Ivanov |first3=A. L.|last4=Littlewood |first4=P. B. |last5=Stolz |first5=H. |date=1999-11-22 |title=LA Phonoritons in Cu{{sub|2}}O |journal=Physical Review Letters |volume=83 |issue=21 |pages=4365–4368 |doi=10.1103/PhysRevLett.83.4365 |bibcode=1999PhRvL..83.4365H}}</ref><ref>{{cite book |last1=Brillouin |first1=Léon |editor1-last=Massey |editor1-first=H. S. W. |title=Wave Propagation and Group Velocity |date=1960 |publisher=Elsevier Science |location=Burlington |isbn=9781483230689}}</ref> | ||
The lowest excitons in Cu<sub>2</sub>O are extremely long lived; absorption lineshapes have been demonstrated with [[electronvolt|neV]] linewidths, which is the narrowest bulk exciton resonance ever observed.<ref>{{cite journal | last1=Brandt | first1=Jan | last2=Fröhlich | first2=Dietmar | last3=Sandfort | first3=Christian | last4=Bayer | first4=Manfred | last5=Stolz | first5=Heinrich | last6=Naka | first6=Nobuko | title=Ultranarrow Optical Absorption and Two-Phonon Excitation Spectroscopy of Cu<sub>2</sub>O Paraexcitons in a High Magnetic Field | journal=Physical Review Letters | publisher=American Physical Society (APS) | volume=99 | issue=21 | date=2007-11-19 | issn=0031-9007 | doi=10.1103/physrevlett.99.217403 | page=217403| pmid=18233254 | bibcode=2007PhRvL..99u7403B }}</ref> The associated quadrupole [[polariton]]s have low [[group velocity]] approaching the speed of sound. Thus, light moves almost as slowly as sound in this medium, which results in high polariton densities. | The lowest excitons in Cu<sub>2</sub>O are extremely long lived; absorption lineshapes have been demonstrated with [[electronvolt|neV]] linewidths, which is the narrowest bulk exciton resonance ever observed.<ref>{{cite journal | last1=Brandt | first1=Jan | last2=Fröhlich | first2=Dietmar | last3=Sandfort | first3=Christian | last4=Bayer | first4=Manfred | last5=Stolz | first5=Heinrich | last6=Naka | first6=Nobuko | title=Ultranarrow Optical Absorption and Two-Phonon Excitation Spectroscopy of Cu<sub>2</sub>O Paraexcitons in a High Magnetic Field | journal=Physical Review Letters | publisher=American Physical Society (APS) | volume=99 | issue=21 | date=2007-11-19 | issn=0031-9007 | doi=10.1103/physrevlett.99.217403 | page=217403| pmid=18233254 | bibcode=2007PhRvL..99u7403B }}</ref> The associated quadrupole [[polariton]]s have low [[group velocity]] approaching the speed of sound. Thus, light moves almost as slowly as sound in this medium, which results in high polariton densities. | ||
Another unusual feature of the [[ground state]] excitons is that all primary scattering mechanisms are known quantitatively.<ref>J. P. Wolfe | Another unusual feature of the [[ground state]] excitons is that all primary scattering mechanisms are known quantitatively.<ref>{{Cite magazine |magazine=[[Scientific American]] |first1=J. P. |last1=Wolfe |first2=A. |last2=Mysyrowicz |title=Excitonic Matter |year=1984 |issue=3 |series=250 |page=98}}</ref> {{chem2|Cu2O}} was the first substance where an entirely parameter-free model of [[absorption (electromagnetic radiation)|absorption]] [[linewidth]] broadening by [[temperature]] could be established, allowing the corresponding [[absorption coefficient]] to be deduced. It can be shown using {{chem2|Cu2O}} that the [[Kramers–Kronig relation]]s do not apply to polaritons.<ref name="Hopfield1958">{{cite journal|last1=Hopfield|first1=J. J.|title=Theory of the Contribution of Excitons to the Complex Dielectric Constant of Crystals|journal=Physical Review|volume=112|issue=5|year=1958|pages=1555–1567|issn=0031-899X|doi=10.1103/PhysRev.112.1555|bibcode=1958PhRv..112.1555H}}</ref> | ||
In December 2021, [[Toshiba]] disclosed a transparent | In December 2021, [[Toshiba]] disclosed a transparent {{chem2|Cu2O}} thin-film [[solar cell]]. The cell achieved an 8.4% [[energy conversion efficiency]], the highest efficiency ever reported for any cell of this type as of 2021. The cells could be used for [[Atmospheric satellite#High-altitude platform station|high-altitude platform station]] applications and [[electric vehicle]]s.<ref>{{cite news |last=Bellini |first=Emiliano |url=https://pv-magazine-usa.com/2021/12/22/toshiba-claims-8-4-efficiency-for-transparent-cuprous-oxide-solar-cell/ |title=Toshiba claims 8.4% efficiency for transparent cuprous oxide solar cell |work=pv magazine |date=2021-12-22 |accessdate=2021-12-22 }}</ref> | ||
==Similar compounds== | ==Similar compounds== | ||
An example of natural copper(I,II) oxide is the mineral [[paramelaconite]], | An example of natural copper(I,II) oxide is the mineral [[paramelaconite]], {{chem2|Cu4O3}} or {{chem2|Cu2^{I}Cu2^{II}O3}}.<ref name=Mindat>{{Cite web|url=https://www.mindat.org/min-3098.html|title=Paramelaconite}}</ref><ref name=IMA>{{Cite web|url=https://www.ima-mineralogy.org/Minlist.htm|title=List of Minerals|date=21 March 2011}}</ref> | ||
==See also== | ==See also== | ||
*[[Copper(II) oxide]] | *[[Copper(II) oxide]] | ||
*[[Copper | *[[Copper oxide]]s | ||
==References== | ==References== | ||
Latest revision as of 00:53, 24 June 2025
Template:Short description Template:Chembox Copper(I) oxide or cuprous oxide is the inorganic compound with the formula Template:Chem2. It is one of the principal oxides of copper, the other being copper(II) oxide or cupric oxide (CuO). The compound can appear either yellow or red,[1] depending on the size of the particles.[2] Cuprous oxide is found as the mineral cuprite. It is a component of some antifouling paints, and has other applications including some that exploit its property as a semiconductor.
Preparation
Copper(I) oxide may be produced by several methods.[3] Most straightforwardly, it arises via the oxidation of copper metal:
Additives such as water and acids affect the rate as well as the further oxidation to copper(II) oxides. It is also produced commercially by reduction of copper(II) solutions with sulfur dioxide.
Alternatively, it may be prepared via the reduction of copper(II) acetate with hydrazine:[2]
Copper(I) chloride solutions react with base to give the same material. In all cases, the color of the cuprous oxide is highly sensitive to the procedural details. Template:Chem2 degrades to copper(II) oxide in moist air.
Formation of copper(I) oxide is the basis of the Fehling's test and Benedict's test for reducing sugars. These sugars reduce an alkaline solution of a copper(II) salt, giving a bright red precipitate of Template:Chem2.
It forms on silver-plated copper parts exposed to moisture when the silver layer is porous or damaged. This kind of corrosion is known as red plague.
Properties
Like all copper(I) compounds, cuprous oxide is diamagnetic. It does not readily hydrate to cuprous hydroxide.
Copper(I) oxide dissolves in concentrated ammonia solution to form the colourless complex Template:Chem2, which is easily oxidized in air to the blue Template:Chem2.
Cuprous oxide is attacked by acids. Hydrochloric acid gives the chloride complex Template:Chem2. Sulfuric acid and nitric acid produce copper(II) sulfate and copper(II) nitrate, respectively.[4]Script error: No such module "Unsubst".
Structure
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In terms of their coordination spheres, copper centres are 2-coordinated and the oxides are tetrahedral. The structure thus resembles in some sense the main [[Silicon dioxide#Crystalline forms|polymorphs of Template:Chem2]], but cuprous oxide's lattices interpenetrate. Template:Chem2 crystallizes in a cubic structure with a lattice constant al = Template:Val. The copper atoms arrange in a Bravais lattice fcc sublattice, the oxygen atoms in a bcc sublattice. One sublattice is shifted by a quarter of the body diagonal. The space group is Pn3m, which includes the point group with full octahedral symmetry.
Applications
The dominant use of cuprous oxide is as a component of antifouling paints.[3]
Cuprous oxide is also commonly used as a pigment and a fungicide.Script error: No such module "Unsubst".
Rectifier diodes based on this material have been used industrially as early as 1924, long before silicon became the standard. Copper(I) oxide is also responsible for the pink color in a positive Benedict's test. In the history of semiconductor physics, Cu2O is one of the most studied materials. Many applications have been demonstrated first in this material:
- Semiconductor diodes[5]
- Phonoritons ("a coherent superposition of exciton, photon, and phonon")[6][7]
The lowest excitons in Cu2O are extremely long lived; absorption lineshapes have been demonstrated with neV linewidths, which is the narrowest bulk exciton resonance ever observed.[8] The associated quadrupole polaritons have low group velocity approaching the speed of sound. Thus, light moves almost as slowly as sound in this medium, which results in high polariton densities. Another unusual feature of the ground state excitons is that all primary scattering mechanisms are known quantitatively.[9] Template:Chem2 was the first substance where an entirely parameter-free model of absorption linewidth broadening by temperature could be established, allowing the corresponding absorption coefficient to be deduced. It can be shown using Template:Chem2 that the Kramers–Kronig relations do not apply to polaritons.[10]
In December 2021, Toshiba disclosed a transparent Template:Chem2 thin-film solar cell. The cell achieved an 8.4% energy conversion efficiency, the highest efficiency ever reported for any cell of this type as of 2021. The cells could be used for high-altitude platform station applications and electric vehicles.[11]
Similar compounds
An example of natural copper(I,II) oxide is the mineral paramelaconite, Template:Chem2 or Template:Chem2.[12][13]
See also
References
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- ↑ Template:Cite magazine
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