Complex sentence: For allenes with four identical substituents, there exist two twofold axes of rotation through the center carbon, inclined at 45 ° to the CH 2 planes at either end of the molecule.
Split into simpler sentences: For allenes with four identical substituents, the compound will have two twofold axes of rotation through the center carbon. These axes are inclined at 45 ° to the CH 2 planes on either side of the molecule.