showed Nb4AlC3 as a minor (~5% from Rietveld refinement) secondary phase. No additional peaks were visible beyond those of the two MAX phases. The Nb4AlC3 diffraction pattern showed a NbC-like impurity (~8%) and a small, broad unindexed peak just above the background signal at 26.7°; no Nb2AlC was detected in the Nb4AlC3 sample. Al NMR spectra of the MAX phases Nb2AlC and Nb4AlC3 are given in Figures and, respectively. For each compound, a simultaneous fit was performed over the static and MAS The static spectra were T1-filtered to facilitate efficient recording of the fast-relaxing MAX signal whereas the MAS spectrum was recorded under quantitative conditions to observe all aluminum environments. Spinning sidebands are denoted with asterisks. See Table for fitting parameters. for fitting parameters. The missing intensity in the fit of the static spectrum is ascribed to the AlO6 environment at ~16 ppm.