Copper Oxide

What is Copper(I) Oxide?

Copper Oxide where copper is in liquid form is called cuprous oxide. Cu2O is the chemical structure of cuprous oxide. Well, here in Cu2O copper and oxygen share a covalent bond; hence it naturally has covalent bonds. Crystals of cuprous oxide are found in cubic shape. When you heat the solution of Cu2O in the presence of hydrogen, the solution is reduced quickly. It is disproportionated in the solution of acid and produces copper and copper (II) ions. Cupric oxide, when heated with the metallic copper, is turned into cuprous oxide. In the presence of moisture in the air, oxygen reacts with copper on the surface of any object and cuprous oxide can act as corrosion resistance in such condition. It will serve as the protective layer of oxide that is thin. 

Copper oxide is a pure compound of all variations of copper compounds. It is noticeable because of usability and versatility in physical property. Superconductivity at the higher temperature, effects of electron correlations, and spin dynamics make the copper oxide to be useful in many ways. Also, its both properties, i.e. chemical and physical, are very stable and hence can be easily mixed with water solutions or polymers. Furthermore, copper oxide is not expensive. 

Other chemical names used for Copper Oxide: Red Cu2O, Cuprous Oxide, and Dicopper Oxide. 

Cu2O Chemical Names: Copper (I) Oxide, Copper (II) Oxide

Physical Properties of Copper Oxide

Copper Oxide Colour

Colour of copper oxide is a bit confusing as sometimes you might have seen red or black coloured copper oxides. Well, here you should have a clear idea that there are two types of copper oxides like copper(I) oxide that is black in colour and copper (II) oxide that is red. 

Other Specifications


Copper(I) Oxide


6 g/cm³

Molecular Weight/ Molar Mass

143.09 g/mol

Boiling Point

1,800 °C

Melting Point

1,232 C

Chemical Formula of Copper oxide


Copper(I) Oxide Structure – Cu2O

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Physical Properties of Copper(I) Oxide – Cu2O


Red-coloured solid


No odour

Covalently-Bonded Unit


Complexity of


Heavy Atom Count    



Insoluble in water

Chemical Properties: Copper(I) Oxide – Cu2O

Copper ( I) Oxide can react with water as the oxygen is present in the water and make Copper (II) Hydroxide. Following is the chemical equation to understand the chemical reaction of copper (I) oxide and water. 

2Cu2O + 4H2O + O2 → 4Cu(OH)2

Through the chemical reaction between hydrogen chloride and copper (I) oxide, Copper (I) Chloride is formed. Well, Oxygen of Copper(I) Oxide is reduced with chlorine atoms and form the copper chloride relatively. You can understand the chemical reaction between hydrogen chloride and Cu2O from the below chemical equation. 

Cu2O + 2HCl → 2CuCl + H2O

Uses of Cu2O Copper Oxide

  • Ship's bottom usually gets affected by seawater, and it is essential to cover the bottom with paint and copper oxide is the best option for antifouling paints. Copper oxide has the property to control the corrosion effectively. 

  • It is a portion of porcelain paints.

  • Photocells for fabricating rectifiers and light meters contain p-type semiconductor that can be carbon oxide. 

  • It can be used as seed dressing and fungicide. 

  • They are used in high-tech superconductors, semiconductors and solar-energy transformation. 

  • Can be implemented in thermoelectric materials, the catalyst, superconducting materials, glass, sensing materials, ceramics and other fields. 

Cupric and Cuprous Oxide: Difference

Copper makes two different oxides according to the valency. Cupric oxide and cuprous oxide. Cupric oxide is a brown colored powder while cuprous oxide is a red coloured. 

When an atom of the copper band is attached to an oxygen molecule, then it is cupric acid. When an oxygen atom is attached to two copper atoms, it is said to be cuprous oxide. Cuprous oxide is mostly in an active state, while cupric oxide is in the fully oxidised state. 

How Copper Oxide is Harmless to Human Beings?

Highly reactive molecules are required to kill the bacteria, and copper oxide is a good puller of electrons. It can also release free radicals and also has the ability to destroy any pathogen if found on the surface. Cuprous oxide is unstable and hence acts quickly then cupric oxide. 

So, we can conclude that cuprous oxide is safe for humans and toxic for bacteria. Well, size also matters when it comes to the ratio between copper oxide cells and several bacteria. 

Preparation of Cuprous Oxide

The most common way copper (I) oxide is formed by oxidation of the copper metal.

4Cu + O2 → 2Cu2O

This happens if you leave copper outside in the air. It is slow as hell (like iron rusting). You can speed it up by adding water and certain acids, but it's still slow.

Copper (I) oxide most commonly made commercially using the other form of copper oxide, copper (II) oxide. You put the copper (II) oxide in a furnace with elemental copper, and a redox reaction takes place, producing copper (I) oxide.

Copper (I) oxide can also be made through the electrolysis of an aqueous solution of sodium chloride between copper electrodes.

FAQ (Frequently Asked Questions)

Question 1: State the Uses Of Cuprous Oxide?

Mainly dye and paints contain copper oxide, especially to paint marine objects like the ship and other tools. It is also an excellent antifouling agent and fungicide. In 1924, when silicon was not in extensive usage, copper oxide worked as silicon in many industries and rectifier diodes. After 1924, silicon gets a standard identity. 

Question 2: Explain the Solubility of Cuprous Oxide in Water.

Well, the cuprous oxide is an organic solvent. Mostly it is insoluble in water, and practically it isn't easy to dissolve it into the water. Furthermore, in an aqueous solution like ammonia, it can be dissolved. It is also soluble in the ammonium salts solution.