Synthesis and characterization of potassium polytellurides in liquid ammonia solution

Ultraviolet-Visible Spectroscopic Investigation of Reaction of Rubidium and Tellurium in Liquid Ammonia Solution

“…This solution was a violet-blue color and exhibited a spectrum with overlapping peaks at about 285 nm and 360 nm and a broad (100-nm) peak at about 560 nm of lesser intensity. This spectrum is very similar to that observed for the ditellurides of both sodium [15] and potassium [16] and is attributed to the formation of Rb 2 Te 2 . 20.5 hours.…”

“…[18] This was verified in this laboratory for reaction of tellurium with sodium [15] and potassium [16] in liquid ammonia, and the same color sequence was observed with rubidium and tellurium. However, reaction times with rubidium were markedly slower than those with sodium and potassium, and the experimental difficulties encountered during filtration prevented obtaining samples of pure stoichiometries.…”

“…This spectrum corresponds to the yellow solution color phase, which has been variously attributed to the Te 2À ion, [18,19] the HTe À ion, [20] or possibly the Te À ion. [15,16] The spectrum for the rubidium species showed its most intense absorption peak at about 330 nm with a broad shoulder (about 50 nm wide) at about 440 nm. This spectrum is similar to that observed for the analogous yellow phase observed with potassium and tellurium, [16] but in the reaction of tellurium and rubidium this peak was the dominant spectral feature for over 6 hr.…”

“…This behavior is also similar to that observed for the formation of the tritellurides of sodium [15] and potassium. [16] Unfortunately, the reaction had to be terminated at this point due to insufficient dry ice supply, and the optical Dewar developed a leak during cleaning that prevented a repeat of this experiment. However, other reactions of rubidium and tellurium in liquid ammonia in reaction flasks on the vacuum line were observed to further proceed to form the characteristic blood red color of the tritelluride.…”

“…Kolis [2] used this technique to prepare polytelluride reagents with potassium, but little information is available to indicate if rubidium might also be a good choice as a metal for polytelluride preparation, although rubidium tellurides that have been synthesized in this manner include Rb 2 Te 2 , [12] Rb 2 Te 3 , [13] and Rb 2 Te 5 . [14] UV-visible spectroscopic studies of the reaction of tellurium with sodium [15] and potassium [16] in liquid ammonia have been reported by this laboratory, and this note describes a similar study of the sequential reactions of tellurium with rubidium with the goal of comparing them to their potassium and sodium analogs.…”