As alternative route, high-temperature solid-state reactions from the elements in different alkali metal to thallium ratios and subsequent quenching to 77 K in liquid nitrogen always yielded a mixture of Rb8Tl11 and Rb15Tl27 (Figure ). Depending on the excess of alkali metal, also elemental rubidium was involved. These results indicate, that binary RbTl is not accessible in experimental settings.