On several new ternary molybdenum sulfide phases M 3.4Mo 15S 19 (M = vacancy, Li, Na, K, Zn, Cd, Sn and Tl)

Abstract

In 3.3Mo 15Se 19 was reported a few years ago, but many attempts to date to prepare the homologue sulfide were unsuccessful. We report herein the first synthesis of In 3.4Mo 15S 19, isostructural to the above selenide and show that indium atoms can be removed from this phase by oxidation with HCl without disturbing the Mo chalcogenide network resulting in a new binary phase Mo 15S 19. Furthermore, this phase, with an open framework structure turns out to be an interesting system for intercalation studies. Indeed, we have shown that Mo 15S 19 can undergo topotactic redox reactions with lithium or sodium resulting in new phases of formula Li 8Mo 15S 19 and Na 8Mo 15S 19 respectively. These two phases are stable at room temperature in the absence of air. Other new ternary compounds M xMo 15S 19, where M = Zn, Cd, Sn and Tl, were also prepared at low temperatures by diffusion of M into the Mo 15S 19 matrix. These phases are stable at room temperature in air. None of the above materials exhibit superconductivity down to 0.5K.