Reactions of F2NC(NO2)(3) with metal fluorides (KF and CsF) in DMF yield a substitution product of the fluorine atom for one nitro group, F2NC(NO2)(2)F. The reaction of F2NC(NO2)(3) with LiBr in ethanol or DMF affords Br(NO2)C=NF rather than the expected bromo derivative F2NC(NO2)(2)Br.