The data reported in this article are structural and physicochemical properties for bare and F, O, OH and CH3O-functionalized Nb n+1C n (n = 1, 2, 3 and 4) MXenes. The structural properties are presented as top views and side views from the X direction of the optimal structures of studied MXenes. The physicochemical properties include quantum capacitances, electrostatic potentials and electroni...