The uranium(IV) azides [Li(THF)3]2[U(OAr)4(N3)2], Ar = 2,6-Me2C6H3, and {[Na(THF)4][U[N(SiMe3)2]3(N3)2]}x have been synthesised and structurally characterised. Oxidation of these complexes affords [Li(THF)3][U(OAr)5(N3)] and U[N(SiMe3)2]3(N3)2, which are the first azides of U(V).
