Tetragonal prismatic structures

The main structural difference between trigonal- and tetragonal-prismatic clusters [12,77] is that not all technetium atoms of the latter are structurally equivalent a pair of technetium atoms situated on the long diagonal of the rhombic base in tetragonal-prismatic clusters have the 2.0 + formal oxidation state, whereas the technetium atoms situated on the short diagonal of these rhombs have the formal oxidation state 1.0 +. However, X-ray photoelectron... 

On the contrary, a trigonal-prismatic polyhedron arrangement is presented by the cluster [Rh6C(CO)15]2. The skeleton structure of the cluster [Co8C(CO)18]2 is a tetragonal antiprism. The structures of more complex carbide clusters are also discussed, for instance [Re8C(CO)24]2, [Os10C(CO)24]2-, and [OsuC(CO)27]2 [25]. 

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