Abstract A range of 3-(para-substituted-phenyl)-3-halodiazirines have been prepared and their 13 C and 19 F NMR spectra measured. Calculated with these data were the susceptibility coefficients ρ I and ρ R of the inductive (σ I) and resonance (σ R 0) effects, respectively, to substituent-induced chemical shift differences at the diazirine carbon (13 C NMR) and the 3-fluorine (19 F NMR of the 3-fluorodiazirine series). An inverse ...