Due to the existence of a lone pair of electrons on each P atom, phosphorene can be easily oxidized. At first, we have investigated the structural stability of PO_x with 0<x<1. For every given 0<x<1 of PO_x, diverse configurations are considered and optimized to find its equilibrium structure to know whether such a phosphorene oxide can be formed or not.

As x increases in PO_x, the electronic properties of phosphorene oxides changes. We found an intriguing phenomenon that at around 16% uniaxial tensile strain, PO (with x=1) becomes a metal with a modified Dirac cone at the gamma point in its Brillouin zone.