This paper reviews the results of XRD, Mossbauer, and H-1, Se-77, and Te-12
5 NMR studies of the structure of iron chalcogenide carbonyl clusters with
a Fe3X (X = Se, Te) framework and a series of their heterometallic derivati
ves synthesized by successive replacement of mononuclear iron carbonyl frag
ments by isolobal metallorganic groups containing Mo and W.