Potassium Oxide - K2O

What is Potassium Oxide?

Potassium oxide is an ionic compound formed by combining potassium and oxygen. It carries the chemical formula K2O. Potassium cannot be found free because it is too reactive. It has valency +1 and combines readily with oxygen atoms forming K2O. The oxide, K2O, is obtained as a grey crystalline substance when potassium is oxidized; potassium burnt in excess oxygen to form potassium oxide. Potassium oxide is a strongly corrosive alkali, which when dissolved in water.

Other names – Potassium monoxide, dipotassium hydroxide, Kalium oxide


Potassium Oxide


2.35 g/cm³

Molecular Weight/ Molar Mass

94.2 g/mol



Melting Point

740 °C

Chemical Formula


Potassium Oxide Structure – K2O

Potassium Oxide

Physical Properties of Potassium Oxide – K2O




Pale yellow solid

Covalently-Bonded Unit


Heat capacity

83.62 J/mol·K




Soluble in EtOH and ether

Chemical Properties of Potassium Oxide – K2O

  • Potassium oxide on treatment with water forms potassium hydroxide. The chemical equation is given below.
  • K2O + H2O → 2KOH

  • Potassium oxide reacts with hydrogen chloride forms potassium chloride and water. The chemical equation is given below.
  • K2O + 2HCl → 2KCl + H2O

Uses of Potassium Oxide – K2O

  • Potassium oxide or “pure potash” expressed as K20, has been designated the commercial standard or unit.
  • Used in farming as a fertiliser, but it can also be used in the manufacture of glass and soap, and in small quantities it is useful for medical purposes.
  • Used to treat fungal granulomatous disease and infections associated with zygomycetes.
  • Used for over 100 years in the treatment of actinomycosis and actinobacillosis in cattle; it is also employed in the treatment of sporotrichosis and botryomycosis.

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