The CF₂ group has found applications as a substituent in all classes of organic chemical products from medicinal products to materials, although it is less frequently encountered than the C–F and CF₃ substituents. In this review, the geometric influence of placing two fluorine atoms on carbon is considered and in particular, deviations from tetrahedral geometry are noted. The incorporation of the CF₂ group into CF₂ phosphonates as phosphate mimics is reviewed and the geometric and steric influences of the CF₂ group are considered when the substituent is placed within aliphatic chains and aliphatic ring (cyclododecane) systems.