Ammonia solution of copper oxide formula

Copper(I) oxide

Copper(I) oxide

or
copper oxide
is an inorganic compound with the formula Cu 2 O. It is one of the main oxides of copper, the other is either copper(II) oxide or copper oxide (CuO). This red solid is found in some antifouling paints. Depending on the particle size, the compound may appear yellow or red. [3] Copper(I) oxide occurs as the reddish mineral cuprite.

Ammonia solution of copper oxide formula

Copper oxide ( I) Cu2 O -
reddish-brown crystals with a cubic crystal lattice, in which linear-tetrahedral coordination of atoms is realized, density 6.1 g/cm 3, melting point 1242°C.

It does not dissolve in water and does not react with it. It has weakly expressed amphoteric properties with a predominance of basic ones.

Interacts with alkali solutions to form hydroxo complexes:

In aqueous solutions of ammonia it forms diammine copper (I) hydroxide:

Reacts with hydrochloric acid to form hydrogen dichlorocuprate (I):

With hydrogen bromide and hydrogen iodide it forms copper (I) salts:

In dilute sulfuric acid it disproportions, forming copper (II) sulfate and metallic copper:

Reduced by hydrogen, carbon monoxide and active metals to metallic copper:

When heated, it is oxidized by atmospheric oxygen:

Copper(I) oxide is produced by electrolysis of a sodium chloride solution using copper electrodes. Hydrogen is released at the cathode, and copper dissolves at the anode to form Cu + ions, and upon interaction with OH groups, Cu2O is formed.

Copper (I) oxide is formed when copper (II) oxide is heated to 1100°C:

or when reducing copper sulfate with glucose or hydrazine in an alkaline medium

:

Copper hydroxide ( I)
CuOH
as an individual compound has not been isolated. When copper(I) salts interact with alkalis in solution, hydrated oxide Cu2O · nH2O is formed, and only Cu2O is released from the solution. When Cu2O is dissolved in alkali solutions, M[Cu(OH)2] is formed.

Source

Preparation[edit]

Copper(I) oxide can be produced in several ways. [4] Simply put, it results from the oxidation of copper metal:

4 Cu + O 2 → 2 Cu 2 O

Additives such as water and acids affect the rate of this process, as well as further oxidation to copper(II) oxides. It is also produced on an industrial scale by reducing copper(II) solutions with sulfur dioxide. Aqueous solutions of cuprous chloride react with a base to form the same material. In all cases, color is very sensitive to the details of the procedure.

Pourbaix diagram for copper in uncomplexed media (except for OH - anions - is not taken into account). Ion concentration 0.001 mol/kg water. Temperature 25°C.

The formation of copper(I) oxide is the basis of the Fehling and Benedict tests for reducing sugars. These sugars reduce the alkaline copper(II) salt solution, giving a bright red precipitate of Cu2O.

It forms on silver-plated copper parts exposed to moisture when the silver layer is porous or damaged. This type of corrosion is known as red plague.

There is little evidence for the existence of copper(I) hydroxide CuOH, which is expected to undergo dehydration quickly. A similar situation applies to gold(I) and silver(I) hydroxides.

Copper(I) oxide

Copper(I) oxide

Copper (I) oxide Cu2O is a brown-red crystalline solid.

Methods for producing copper (I) oxide

In the laboratory, copper(I) oxide is prepared by reducing freshly precipitated copper(II) hydroxide, for example with aldehydes or glucose:

Chemical properties of copper (I) oxide

1. Copper (I) oxide has basic properties.

When copper (I) oxide is treated with hydrohalic acids, copper (I) halides and water are obtained:

For example , hydrochloric acid with copper(I) oxide forms copper(I) chloride:

Cu2O + 2HCl = 2CuCl↓ + H2O

2. When Cu2O is dissolved in concentrated sulfuric and nitric acids, only copper (II) salts are formed:

3. Stable copper (I) compounds are insoluble compounds (CuCl, Cu2S) or complex compounds [Cu(NH3)2] +. The latter are obtained by dissolving copper (I) oxide and copper (I) chloride in a concentrated solution of ammonia:

Ammonia solutions of copper (I) salts react with acetylene :

СH ≡ CH + 2[Cu(NH3)2]Cl → СuC ≡ CCu + 2NH4Cl

4. In redox reactions, copper (I) compounds exhibit redox duality:

For example , when interacting with carbon monoxide, more active metals or hydrogen, copper (II) oxide exhibits the properties of an oxidizing agent :

Ammonia solution of copper oxide formula

Copper oxide ( II)
CuO
- black crystals, crystallizes in a monoclinic system, density 6.51 g/cm 3, melting point 1447 ° C (under oxygen pressure). When heated to 1100°C, it decomposes to form copper (I) oxide:

It does not dissolve in water and does not react with it. It has weakly expressed amphoteric properties with a predominance of basic ones.

In aqueous solutions of ammonia it forms tetraammine copper (II) hydroxide:

Reacts easily with dilute acids to form salt and water:

When fused with alkalis it forms cuprates:

Reduced by hydrogen, carbon monoxide and active metals to metallic copper:

It is obtained by calcining copper (II) hydroxide at 200°C:

or during the oxidation of copper metal in air at 400–500°C:

Copper (II) hydroxide Cu(OH)2

– a blue substance, exists in amorphous and crystalline forms, the crystal lattice is rhombic, density 3.37 g/cm 3, when heated above 70°C, it decomposes into copper (II) oxide and water:

Poorly soluble in water. It has weakly expressed amphoteric properties with a predominance of basic ones.

Reacts easily with acids to form salts:

In aqueous solutions of alkalis it forms unstable bright blue hydroxo complexes:

In ammonia solution there are stable ammonia compounds of dark blue color:

Displaying basic properties, it interacts with carbon dioxide to form the main copper (II) carbonate – malachite:

Obtained by the exchange interaction of copper (II) salts and alkali

:

crystalline copper (II) hydroxide is formed by introducing sodium or potassium hydroxide into an ammonia solution of copper (II) sulfate:

Source

Semiconductor properties[edit]

In the history of semiconductor physics, Cu2O is one of the most studied materials, and many experimental applications of semiconductors were first demonstrated in this material:

• Semiconductor
• Semiconductor diodes [6]
• Phonoritons ("coherent superposition of exciton, photon and phonon") [7][8]

The lowest excitons in Cu 2 O are extremely long-lived; the shape of the absorption lines has been demonstrated with a neV linewidth that is the narrowest bulk exciton resonance ever observed. [9] The corresponding quadrupole polaritons have a low group velocity, approaching the speed of sound. Thus, in this environment, light travels almost as slowly as sound, resulting in a high density of polaritons. Another unusual feature of ground state excitons is that all primary scattering mechanisms are known quantitatively. [10] Cu 2 O was the first substance in which a completely parameter-free model of absorption linewidth broadening with temperature could be established, allowing the corresponding absorption coefficient to be derived. Using Cu 2 O, it can be shown that the Kramers–Kronig relations do not apply to polaritons. [eleven]

Copper(I) oxide

Copper(I) oxide

(copper hemioxide, dicopper oxide,
obsolete
copper oxide) is a chemical compound with the formula Cu2O. Compound of copper with oxygen, basic oxide. Brown-red crystalline substance. It occurs in nature as the mineral cuprite.

Links[edit]

1. https://www.nwmissouri.edu/naturalsciences/sds/c/Copper%20I%20oxide.pdf
2. ^ abc NIOSH Pocket Guide to Chemical Hazards. "#0150" . National Institute of Occupational Safety and Health (NIOSH).
3. N.N. Greenwood, A. Earnshaw, Chemistry of the Elements
   , 2nd ed., Butterworth-Heinemann, Oxford, UK, 1997.
4. H. Wayne Richardson "Copper Compounds in Ullman's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. Doi: 10.1002 / 14356007.a07_567″
5. D. Nicholls, First Line Complexes and Transitions
   , Macmillan Press, London, 1973.
6. L.O. Grondal, Unidirectional current device, patent, 1927
7. Hanke, L.; Fröhlich, D.; Ivanov, AL; Littlewood, PB; Stolz, H. (1999-11-22). "LA Phonoritons in Cu 2 O". Physics Review Letters
   .
   83
   (21):4365–4368. DOI: 10.1103/PhysRevLett.83.4365.
8. L. Brillouin: Wave Propagation and Group Velocity
   , Academic Press, New York, 1960 ISBN 9781483276014.
9. J. Brandt, D. Fröhlich, K. Sandfort, M. Bayer, H. Stolz and N. Naka, Ultranarrow absorption spectroscopy and two-phonon excitation of Cu 2 O paraexcitons in a strong magnetic field
   , Phys. Rev. Lett. 99, 217403 (2007). DOI: 10.1103/PhysRevLett.99.217403
10. J. P. Wolf and A. Mysyrowicz: Exciton Substance, Scientific American 250
    (1984), No. 3, 98.
11. Hopfield, J. J. (1958). "Theory of the contribution of excitons to the complex dielectric constant of crystals." Physical Review
    .
    112
    (5):1555–1567. DOI: 10.1103/PhysRev.112.1555. ISSN 0031-899X.
12. https://www.mindat.org/min-3098.html
13. https://www.ima-mineralogy.org/Minlist.htm

Chemical properties

Reactions in aqueous solutions

Copper(I) oxide does not react with water. To a very small extent (PR = 1.2⋅10 −15) dissociates:

Copper (I) oxide is transferred into solution:

• concentrated hydrochloric acid

Cu2O + 4HCl ⟶ 2H[CuCl2] + H2O

• concentrated alkali (partially)

Cu2O + 2OH − + H2O ⇄ 2[Cu(OH)2] −

• concentrated ammonia hydrate and concentrated solutions of ammonium salts

Cu2O + 4(NH3 ⋅ H2O) ⟶ 2[Cu(NH3)2]OH + 3H2O Cu2O + 2NH4 + ⟶ 2[Cu(H2O)(NH3)] +

• by oxidation to copper (II) salts with various oxidizing agents (for example, concentrated nitric and sulfuric acids, oxygen in dilute hydrochloric acid)

Cu2O + 6HNO3 ⟶ 2Cu(NO3)2 + 2NO2↑ + 3H2O Cu2O + 3H2SO4 ⟶ 2CuSO4 + SO2↑ + 3H2O 2 Cu2O + 8HCl + O2 ⟶ 4CuCl2 + 4H2O

Also, copper (I) oxide enters into the following reactions in aqueous solutions:

• slowly oxidized by oxygen to copper(II) hydroxide

2 Cu2O + 4H2O + O2 ⟶ 4Cu(OH)2↓

• reacts with dilute hydrohalic acids to form the corresponding copper(I) halides:

Cu2O + 2HHal ⟶ 2CuHal↓ + H2O (Hal = Cl, Br, I)

• in dilute sulfuric acid dismutates into copper (II) sulfate and metallic copper

Cu2O + H2SO4 ⟶ CuSO4 + Cu↓ + H2O

• reduced to copper metal by typical reducing agents, e.g. sodium hydrogen sulfite in concentrated solution

2 Cu2O + 2NaHSO3 ⟶ 4Cu↓ + Na2SO4 + H2SO4

Reactions at high temperatures

Copper(I) oxide is reduced to copper metal in the following reactions:

• when heated to 1800 °C (decomposition)

2 Cu2O → 1800∘C 4Cu + O2

• when heated in a stream of hydrogen, carbon monoxide, with aluminum

Cu2O + H2 → >250∘C 2Cu + H2O Cu2O + CO → 250−300∘C 2Cu + CO2 3 Cu2O + 2Al → 1000∘C 6Cu + Al2O3

• when heated with sulfur

2 Cu2O + 3S → >600∘C 2Cu2S + SO2 2 Cu2O + Cu2S → 1200−1300∘C 6Cu + SO2

Copper(I) oxide can be oxidized to copper(II) compounds in a stream of oxygen or chlorine:

Also, at high temperatures, copper (I) oxide reacts:

• with ammonia (copper(I) nitride is formed)

3 Cu2O + 2NH3 → 250∘C 2Cu3N + 3H2O

• with oxides of alkali metals and barium (double oxides are formed)

Cu2O + M2O → 600−800∘C 2MCuO Cu2O + BaO → 500−600∘C BaCu2O2

Other reactions

Copper(I) oxide reacts with hydrogen azide:

• upon cooling, a precipitate of copper (II) azide precipitates

Cu2O + 5HN3 → 10−15∘C 2Cu(N3)2↓ + H2O + NH3↑ + N2↑

• at room temperature in a stream of hydroazidic acid a precipitate of copper (I) azide precipitates

Cu2O + 2HN3 → 20−25∘C 2CuN3↓ + H2O

Receipt

Copper(I) oxide can be prepared:

• heating copper metal in the absence of oxygen

4Cu + O2 → >200∘C 2 Cu2O

• heating copper metal in a stream of nitric oxide (I) or nitric oxide (II)

2Cu + N2O → 500−600∘C Cu2O + N2 4Cu + 2NO → 500−600∘C 2 Cu2O + N2

• heating copper metal with copper(II) oxide

Cu + CuO → 1000−1200∘C Cu2O

• thermal decomposition of copper (II) oxide

4CuO → 1026−1100∘C 2 Cu2O + O2

• heating copper(I) sulfide in a stream of oxygen

2Cu2S + 3O2 → 1200−1300∘C 2 Cu2O + 2SO2

In the laboratory, copper(I) oxide can be prepared by reducing copper(II) hydroxide (for example, with hydrazine):

Also, copper(I) oxide is formed in ion exchange reactions of copper(I) salts with alkalis, for example:

• in the reaction of copper (I) iodide with a hot concentrated solution of potassium hydroxide

2CuI + 2KOH ⟶ Cu2O ↓ + 2KI + H2O

• in the reaction of hydrogen dichlorocuprate (I) with a dilute solution of sodium hydroxide

2H[CuCl2] + 4NaOH ⟶ Cu2O ↓ + 4NaCl + 3H2O

The last two reactions do not produce a compound with a composition corresponding to the formula CuOH (copper (I) hydroxide). The formation of copper (I) oxide occurs through an intermediate hydrate form of variable composition Cu2O ⋅ xH2O.

• Oxidation of aldehydes with copper (II) hydroxide. If an aldehyde solution is added to the blue precipitate of copper (II) hydroxide and the mixture is heated, then a yellow precipitate of copper (I) hydroxide appears first:

R−CHO + 2Cu(OH)2 → t R−COOH + 2CuOH↓ + H2O upon further heating, the yellow precipitate of copper (I) hydroxide turns into red copper (I) oxide: 2CuOH → t Cu2O + H2O