Polychalcogenides polysulfides

Polychalcogenides are less stable than polysulfides (p. 681). Reaction of alkali metals with Se in liquid ammonia affords M2Se2, M2Se3 and M2Se4, and analogous polytellurides have also been reported (see preceding section). However many of these compounds are rather unstable thermally and tend to be oxidized in air. 

The field of polysulfide complexes has been reviewed earlier.347 A more recent survey covers polychalcogenide complexes in general,348 and in a review on ate complexes also further examples of anionic polychalcogenide species are dealt with.349... 

Metal sulfides and polysulfides have been extensively studied because of their key role in important catalytic processes such as the hydrodesulfurization of crude oil or the biosynthesis of metalloproteins. The coordination chemistry of polysulfides85 86 has been comprehensively reviewed similar to that of the heavier polychalcogenides.10,12 15 Polysullido complexes are themselves reactive and their exothermic desulfurization can be exploited as a means of... 

In 1976, the first regenerative PECs with substantial and sustained solar to electrical conversion efficiency were demonstrated. These PECs are based on n-type cadmium chalcogenide (S, Se or Te) electrodes immersed in aqueous polychalcogenide electrolytes. The cells were introduced by Hodes, Cahen, and Manassen (31), Wrighton and coworkers [32], and Heller and Miller [33] and were capable of converting up to 7% of insolation to electrical energy. Most investigations of these systems focused on solid-state and interfacial aspects of these PECs and photodriven oxidation of polysulfide at the photoelectrode was represented ... 

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