Chapter 3, Problem 3.36P

Although the $\text{C}—\text{F}$ distances and the $\text{F}—\text{C}—\text{F}$ bond angles differ considerably in ${\text{F}}_{\text{2}}\text{C}\equiv {\text{CF}}_{\text{2}},{\text{F}}_{\text{2}}\text{CO},{\text{CF}}_{\text{4}}$ , and ${\text{F}}_{\text{3}}{\text{CO}}^{-}$ ( $\text{C}—\text{F}$ distances 131.9 to 139.2 pm: $\text{F}—\text{C}—\text{F}$ bond angles 101.3° to109.5°), the F...F distance in all four structures is very nearly the same (215 to 218 pm). Explain,using the LCP model of Gillespie. (See R. J, Gillespie, Coord. Chem. Rev., 2000. 197, 51.)