| Abstract
| - Theimportance of the tellurium-to-metal electron transfers resulting fromthe Te···Te short contacts in the layered ternarytelluridesTa3Pd3Te14and Ta4Pd3Te16 isdiscussed. The large electron transfers originating from thebicapped trigonal prismatic chains of the layers lead to difficultiesin assigning meaningful oxidation states. It is shown that theinterlayer Te···Te interactions have a strong control of theconductivity of these phases.
- The electronic structures of the layered ternary telluridesTa3Pd3Te14 andTa4Pd3Te16 are examined.It is foundthat the presence of bicapped trigonal prismatic chains with extensiveTe···Te interactions results in very widetellurium-based bands along the direction of the chains. The localoctahedral coordination of the Pd and onetype of Ta atoms, as well as additional short Te···Tecontacts, allows for the participation of the remainingchains of the layer in such a delocalization. This leads to largetellurium to metal electron transfers and difficultiesin proposing meaningful oxidation states for the Pd and Ta atoms.The interlayer Te···Te interactions arefoundto exert a strong control of the density of states at the Fermi leveland, hence, of the conductivity of these phases.The results are also compared with those forTa3SiTe6, a structurally different layeredternary telluride with shortTe···Te contacts. For this phase, meaningful oxidationstates for the Ta and Si atoms can be proposed. Thedifferent, but important, role of interlayer Te···Teinteractions in Ta3SiTe6 is alsodiscussed.
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