Phosphorus oxide can refer to:
Between the commercially important P<sub>4</sub>O<sub>6</sub> and P<sub>4</sub>O<sub>10</sub>, several other, less common oxides of phosphorus are known. Specifically, P<sub>4</sub>O<sub>7</sub>, P<sub>4</sub>O<sub>9</sub>, and P<sub>2</sub>O<sub>6</sub> all bear structures intermediate between the endmembers:
On observation it will be seen that double bonded oxygen in P<sub>4</sub>O<sub>8</sub> at 1,2 position or 1,3 position are identical and both positions have same steric hindrance. Cycle 12341 and ABCDA are identical.
Gases: