text: F-F coupling constants are generally larger than H-H coupling constants.  Long range F-F coupling, (J, J, J or even J) are commonly observed.  Generally, the longer range the coupling, the smaller the value. Hydrogen couples with fluorine, which is very typical to see in F spectrum.  With a geminal hydrogen, the coupling constants can be as large as 50 Hz.  Other nuclei can couple with fluorine, however, this can be prevented by running decoupled experiments. It is common to run fluorine NMRs with both carbon and proton decoupled. Fluorine atoms can also couple with each other.  Between fluorine atoms, homonuclear coupling constants are much larger than with hydrogen atoms.  Geminal fluorines usually have a J-value of 250-300 Hz.  There are many good references for coupling constant values.  The citations are included below.