Sodium Oxide (Na2O)

What is Sodium Oxide?

Sodium oxide is an alkali metal oxide with the chemical formula Na2O.

It is the anhydride form of sodium hydroxide. When sodium burns in the air it burns with a bright, white light. When it burns in oxygen it burns even more brightly. It forms a white powder called sodium oxide. Within the earth’s crust, sodium ions often combine with the oxygen in soil and rocks to form sodium oxide (Na2O), one of the most common forms of sodium.

Other names – Disodium oxide, Disodium monoxide

Na2O Sodium Oxide
Density 2.27 g/cm³
Molecular Weight/ Molar Mass 61.9789 g/mol
Boiling Point 1,950 °C
Melting Point 1,132 °C
Chemical Formula Na2O

Structure of Na2O Molecules

Sodium oxide molecules are made up of two sodium cations and one oxygen anion. Thus, Na2O molecules feature two sodium-oxygen ionic bonds. The structure of sodium oxide molecules is illustrated below.

Sodium Oxide

Physical Properties of Sodium Oxide – Na2O

Odour Odourless
Appearance White solid
Covalently-Bonded Unit 3
Heat capacity 72.95 J/(mol·K)
Hydrogen Bond Acceptor 1
Solubility Reacts with water and ethanol.

Chemical Properties of Sodium Oxide – Na2O

    • Sodium oxide reacts with carbon dioxide to form sodium carbonate. The chemical equation is given below.

2Na2O + 3CO2 → 2Na2CO3

    • Sodium oxide reacts with some acids (such as hydrochloric acid) to form sodium chloride and water. The chemical equation for this reaction is given below.

Na2O + HCl → NaCl + H2O

Uses of Sodium Oxide – Na2O

  • It is an active flux and used to create glazes which give exciting colour responses. The more notable responses are blue from copper oxide and purple from cobalt and manganese oxides.
  • Used in bodies except where it has been introduced primarily as a deflocculant for casting slips.
  • Sodium oxide is also used in the manufacture of commercial glasses based on the oxides of silicon and certain additives.

Frequently Asked Questions – FAQs

What is sodium oxide used for?

Sodium oxide is used in the manufacture of glass and ceramic products. It is also used in the production of sodium hydroxide (which can be obtained by adding water to anhydrous sodium oxide).

Is sodium oxide a salt?

Sodium oxide can be considered as an ionically bonded solid ceramic. This metal oxide is insoluble in water and will react if exposed to water to form sodium hydroxide.

Is sodium oxide toxic?

Sodium oxide is converted into sodium hydroxide when exposed to water, which can be highly corrosive and cause burns to any human tissue that it comes in contact with. Therefore, sodium oxide must be handled with care.

How can sodium oxide be prepared?

Sodium oxide can be produced by reacting metallic sodium with sodium hydroxide. The chemical equation for this reaction is:

2Na + 2NaOH → H2 + 2Na2O

An alternate method for the preparation of sodium oxide is by reacting sodium nitrite with sodium. The balanced chemical equation for this reaction is given by:

6Na + 2NaNO2 → N2 + 4Na2O

Here, the reaction between two molar equivalents of sodium nitrite and six molar equivalents of sodium yields one molar equivalent of dinitrogen gas and four molar equivalents of sodium oxide.

Is sodium oxide soluble in water?

No, sodium oxide is not soluble in water. Na2O reacts violently when exposed to water, forming sodium hydroxide in the process. Therefore, sodium oxide must be kept away from water and stored in a dry environment.

To learn more about sodium oxide and other important chemical compounds containing sodium (such as sodium bicarbonate), download BYJU’S – The Learning App.

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