Calculations on FOC(O)OF are reported at the B3LYP/6-311+G(2df)//B3LYP/6-31+G(d)+ZPC level of theory. The molecule is predicted to exist as a mixture of rotamers. The lowest-energy rotamer, the synanti, is predicted to be planar. The syn-syn rotamer appears to be conformationally floppy; a nonplanar (C-2) form, with O-F bonds rotated from the CO3 plane by 16.4 degrees, and a planar (C-2v) form are separated by only 0.01 kcal/mol. The anti-anti rotamer is predicted to be nonplanar (Ct symmetry); the O-F bonds are rotated out of the CO3 plane by 27.9 degrees. Calculated barriers for interconversion of rotamers are less than 10 kcal/mol. We also calculate vibrational frequencies for the rotamers. The calculated O-F bond enthalpy is 30.2 kcal/mol.