In contrast to stable phosphorus oxides such as P4O6 and P4O10 that possess iconic adamantane-like cage structures, highly reactive phosphorus oxides such as PO, PO2, and P2Ox (x = 1-5) only have been studied in the gas phase or by matrix isolation techniques. Elusive diphosphorus tetroxide, the long sought phosphorus analogue of N2O4, is particularly noteworthy. Computations predict that the oxo-bridged O2POPO form of P2O4 is energetically more favored than the P-P bonded O2P-PO2 isomer. Herein, we report the experimental realization of diphosphorus tetroxide-in its energetically disfavored O2P-PO2 form-via carbene-stabilization. The synthesis of the title compound involves the splitting of molecular oxygen by carbene-stabilized diphosphonis.