The -F terminations, on the other hand, are observed at higher frequencies for the Nb MXenes than for V2CTx and Ti3C2Tx, which could be due to more covalent Nb-F bonding caused by the more diffuse 4d orbitals. In general, the multiple NMR signals observed for -OH and -F terminations, and the dependence on the synthesis, can be ascribed to distinct local environments due to different arrangements of the surface terminations (-OH, -O, -F and termination vacancy), as well as interlayer H2O, as shown, for instance, for the -F terminations in Nb4C3Tx. .