CF2

CF2 is a chemical notation that can refer to two related concepts in fluorine chemistry: the difluoromethylene group -CF2- and the difluorocarbene :CF2. The intended meaning depends on the context of the discussion or the drawing of a structure.

In organic molecules and polymers, the difluoromethylene group symbolizes a carbon atom bonded to two fluorine atoms, typically linking two other fragments. The CF2 unit occurs in fluoropolymers such as polyvinylidene fluoride (PVDF) and in various difluoromethylated motifs. The presence of two strong C–F bonds affects polarity, thermal stability, dielectric properties, and metabolic behavior, making CF2-containing motifs valuable in materials science and medicinal chemistry.

Difluorocarbene, symbolized as :CF2, is a highly reactive, divalent carbon species that is normally generated in situ. It participates in cyclopropanation of alkenes to yield gem-difluorocyclopropanes and can insert into X–H or C–H bonds under appropriate conditions. Because of its reactivity, generation methods rely on precursors that release CF2 under heat, light, or in the presence of base.

As a general shorthand, CF2 also denotes the difluoromethylene fragment -CF2- in structural formulas, spanning refinery feedstocks, pharmaceuticals, and materials where fluorinated carbon segments replace hydrogen-containing regions.

See also: difluoromethyl group, difluorocarbene, polyvinylidene fluoride, PTFE, fluoropolymer.