Fig. 3: ²⁷Al DQ-SQ 2D NMR spectrum.

a ²⁷Al 2D NMR spectrum recorded at 18.8 T with ν_R = 20 kHz of SA/50 dehydrated at 723 K for 12 h under vacuum. b–f Rows extracted from the 2D spectrum corresponding to the various auto-correlations and cross peaks. All rows are plotted with the same intensity scale.