or 256-560 scans ( 71 Ga) were summed. For Ga and Ga spectra collected at 35 kHz MAS with the 1.6 mm probe, an excitation pulse of 1.0 µs was applied; 56,480 scans with a recycle delay of 1 s were summed for Ga and 17,800 scans with a recycle delay of 3 s were summed for Ga. 1.0 M Ga(NO 3 ) 3(aq.) at 0.0 ppm, 72 0.1 M In(NO 3 ) 3 in 0.5 M HNO 3 at 0.0 ppm, and saturated Bi(NO 3 ) 3 in concentrated HNO 3 at 0.0 ppm were used as NMR shift references.