Liquid ammonia was condensed on sodium and kept under argon, cooled by a dry ice/ ethanol bath. Anhydrous ammonia (5 mL) was condensed on the mixture of reactants ((1) 2 Rb + TlBF4, (2) 2 Rb + TlPF6, and (3) 2 Rb + TlBr) in three times baked-out reaction vessels and stored at 233.15 K. The approaches were prepared and stored at 233.15 K. After two to five days, ammonia was evaporated and the residue was characterized by X-ray powder diffraction (see SI, chapter 4).