First attempts for the synthesis of binary RbTl were carried out by the historical low-temperature experiments in anhydrous liquid ammonia. There, elemental rubidium and thallium(I) salts are reacted in a 2:1 (Rb: Tl(I)X (X=Br, BF4, PF6)) ratio at low temperature, which is a well-known preparation route for NaTl. The variation of the anion from Tl(I)X (X=Cl, Br, I) to weakly coordinating anions like [BF4] -or [PF6] -was also tested. All approaches resulted in elemental thallium and a rubidium salt, formed by Br -or the weakly coordinating anion (see PXRD in SI chapter 4). The low-temperature route therefore seems to be limited to NaTl.