Since niobium atoms are located at the outer surface of the 2D MXene sheets, the number of distinct Nb local environments and NMR signals depends on the surface terminations. The 93 Nb lineshape of Nb2CTx was simulated with two quadrupolar lines, providing a reasonable fit to the data (Figure ); the minor but sharper signal is consistent with Nb2AlC, the broader signal was attributed to Nb2CTx and was fit with diso = -790(30) ppm, CSA = -350(50) ppm, hCSA = 0.5(3), CQ = 77(3) MHz, hQ = 0.2(1), Euler angles a,b,g = 0°, 50(10)°, 0°. The CQ for Nb2CTx is more than double that of Nb2AlC, providing spectral evidence for the reduction of symmetry at the MXene surface. Furthermore, the non-zero ηQ indicates a breaking of the threefold symmetry of the Nb site at the surface, presumably due to the surface terminations.