Phosphorus oxide (III)

Phosphorus trioxide. Phosphorus (III) oxide, diphosphorus trioxide or phosphorous anhydride (of formula P2O3) is the anhydride of the unstable tautomer of phosphorous acid. It is also a ligand for transition metals. Preparation

Phosphorus oxide (xx) is obtained by combustion of tetra- phoric phosphorus:

P4 + 3 O2 → hollow Chemical properties

1. Phosphorus oxide (III) reacts with cold water to obtain phosphorous acid (H3PO3): P2O3 + 3 H2O → 2 H3PO3

2. Phosphorus oxide (III) reacts vigorously with hot water to obtain flammable phosphine (PH3) and phosphoric acid: P4O6 + 6 H2O → PH3 ↑ + H3PO4

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