The structures and IR spectra of CF3OCH3, CF3OCF2H, and CF3OCF2CF2H and corresponding alkanes CF3CH3, CF3CF2H, and CF3CF2CF2H have been calculated using the B3LYP method with a 6-311G(2d,2p) basis set. The calculated IR spectra are consistent with, and provide additional confidence in, the available experimental data.