Condensed Metal Clusters

Abstract The chemistry of metals in low valence states is marked by the frequent occurrence of metal clusters, which are easily recognizable when they occur as molecular units. Many metal‐rich compounds of transition metals with p‐elements (3rd to the 6th main groups) are closely related to the corresponding halides, since they are built up from metal clusters of the same type. The clusters are however, linked together (condensed) by metal‐metal bonds. This principle of construction holds particularly well in the case of the novel reduced halides of the lanthanoids.