Difluoromethylenation of C60 with thermally decomposed CF2ClCO2Na provides novel C60(CF2) and C60(CF2)2 compounds with unique [6,6]-open structures. A theoretical survey of CF2 derivatives of C60 demonstrates that carbon cage opening can be controlled via charging of the molecule and that the thermodynamically preferable structures combine the trend to form open isomers with the compactness of the addition motifs, which results in the formation of windows in the fullerene cage.