figure_2_description.txt

# Experimental (dark blue) and fitted (dashed red) $^{87}$Rb MAS (30 kHz), $^{93}$Nb CTMAS (100 kHz), and 3QMAS (30 and 100 kHz for $^{87}$Rb and $^{93}$Nb, respectively) NMR (20 T) spectra of RbNb$_{2}$O$_{5}$F (\textit{a}, \textit{c}, \textit{d}, and \textit{f}) and RbTa$_{2}$O$_{5}$F (\textit{b} and \textit{e}). The insets represent zooms of the central transition (top-left of \textit{a}, \textit{b}, and \textit{c}) and the three first-order satellite transitions (top-right of \textit{a} and \textit{b}). The individual resonance used for the fit (teal), the zeroth-order satellite transition spinning sidebands (orange), and the model difference (grey) are shown below the spectra. For each 3QMAS spectrum, the diagonal with a unity slope (light orange) and projections along (\textit{MAS}, \textit{Intensity}) and (\textit{Isotropic}, \textit{Intensity}) are presented.