To elucidate the structures of C60F36 and C60F48, X-ray diffraction and electron diffraction experiments have been performed. It was found that the X-ray diffractograms of C60F36 and C60F48 at room temperature are indexed by bce and bet lattices, respectively. In situ X-ray diffraction experiments at high temperatures have been also undertaken. The bet to fee phase transition of C60F38 was observed. The mechanism of the transition and the stabilities of the structures of fluorinated fullerenes are discussed.