upgrade

💏intro to chemistry review

Phosphorus(III) Oxide

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Phosphorus(III) oxide, also known as phosphorous oxide or phosphorus trioxide, is a chemical compound with the formula P4O6. It is an important intermediate in the production and use of phosphorus and its various compounds, particularly in the context of the occurrence, preparation, and properties of phosphorus.

5 Must Know Facts For Your Next Test

  1. Phosphorus(III) oxide is a colorless, crystalline solid that is formed when phosphorus is burned in a limited supply of oxygen.
  2. It is an important intermediate in the production of various phosphorus-containing compounds, including phosphoric acid and phosphate fertilizers.
  3. Phosphorus(III) oxide is highly reactive and readily undergoes hydrolysis to form phosphorous acid (H3PO3), which can then be further oxidized to phosphoric acid (H3PO4).
  4. The oxidation state of phosphorus in phosphorus(III) oxide is +3, which is lower than the +5 oxidation state found in phosphoric acid (H3PO4).
  5. Phosphorus(III) oxide is used in the production of various flame retardants, pesticides, and other industrial chemicals.

Review Questions

  • Describe the formation and chemical properties of phosphorus(III) oxide.
    • Phosphorus(III) oxide is formed when phosphorus is burned in a limited supply of oxygen. It is a colorless, crystalline solid that is highly reactive and undergoes hydrolysis to form phosphorous acid (H3PO3). The oxidation state of phosphorus in phosphorus(III) oxide is +3, which is lower than the +5 oxidation state found in phosphoric acid (H3PO4). Phosphorus(III) oxide is an important intermediate in the production of various phosphorus-containing compounds, including phosphoric acid and phosphate fertilizers.
  • Explain the role of phosphorus(III) oxide in the occurrence, preparation, and properties of phosphorus.
    • Phosphorus(III) oxide is a key intermediate in the production and use of phosphorus and its various compounds. It is formed during the occurrence and preparation of phosphorus, as a result of the partial oxidation of phosphorus. The properties of phosphorus(III) oxide, such as its reactivity and ability to undergo hydrolysis, are important in understanding the broader context of the occurrence, preparation, and properties of phosphorus. Phosphorus(III) oxide is also used in the production of various phosphorus-containing chemicals and materials, which are relevant to the properties and applications of phosphorus.
  • Analyze the significance of the oxidation state of phosphorus in phosphorus(III) oxide and its relationship to other phosphorus compounds.
    • The oxidation state of phosphorus in phosphorus(III) oxide is +3, which is lower than the +5 oxidation state found in phosphoric acid (H3PO4). This difference in oxidation state is crucial in understanding the chemical properties and reactivity of phosphorus(III) oxide, as well as its role in the broader context of phosphorus chemistry. The ability of phosphorus to exist in different oxidation states allows for the formation of a variety of phosphorus-containing compounds, each with their own unique properties and applications. Analyzing the significance of the oxidation state in phosphorus(III) oxide and its relationship to other phosphorus compounds, such as phosphoric acid, provides valuable insights into the occurrence, preparation, and diverse properties of phosphorus.