Sulfide compounds cluster anions

The area of germanium sulfide cluster anions has been enriched by the publication of a number of new compounds. The structure of the quaternary germanium sulfide AgLasGeSg has been elucidated and shown to comprise La3GeS4 cubes linked through Ge—S bonds to form a three dimensional arrayIn contrast, the anion [CuGe2S5] comprises [Ge4Sio]" units. ... 

Several iron sulfide nitrosyl compounds are known. These have stmctures that in some cases are formally related to the FeS clusters by replacement of thiolate by NO. The compounds include the anions [Fe2S2(NO)4] and [Fe4S2(NO)2] (Roussin s red and black salts, respectively) and the neutral compounds [Fe2S2(NO)4] and [Fe4S4(NO)4]. Roussin s black salt has found use as a NO releasing vasodilator. 

Nitride halides and nitride sulfides constitute another family of rare-earth-containing compounds. The variety concerns the richness of the different formulations as well as the nature itself of the compounds. Except in the case of nitride fluorides which have a clear salt behavior, nitrogen atoms generally do not play the same role as Cl" or S anions in some cases it is even difficult to know whether the borderline between a valence compound and a cluster compound has not been crossed. 

---