The reactants, products, and the transition state for the reaction CF2O + O = CF2O2 have been investigated using ab initio molecular orbital theory at the MP2 level. Geometry optimizations and vibrational frequency calculations have been performed on all reactants, products, and the transition state at both the MP2/3-21G** and the MP2/6-311G** levels. Most of the calculations have been carried out assuming the oxygen atom was in its lowest triplet state and that the transition state and the product were also in their lowest triplet states. However additional calculations have determined the structure and energy of the singlet ground state of CF2O2 and of its lowest singlet excited state. This provides a detailed picture of the thermodynamics of the reaction of CF2O with either singlet or triplet oxygen to give the singlet, closed shell CF2O2.