A new increasing delocalization of M=3d-elements (Ti, Fe, Co) in the channels network of the ternary MyMo6Se8 Chevrel phases

摘要

A structural investigation on single crystals of MyMo6Se8 Chevrel phases (M = 3d: Ti, Fe, and Co) has been carried out. These latter compounds as well as others with Cr, Mn, and Ni atoms make part of a new original family of Chevrel phases. The M ions occupy new interstices in the tridimensional channels network never observed in the other classical Chevrel phases as Li-y, Cu-y Mo6X8. They occupy only cavity 2 centered on ((1)/(2)00) and hooked left arrow with a progressive delocalization of the M cation versus the nature of the cation from the center of the cavity to the outside. The position in cavity 2 is different from the position of the Cu (2) atoms, the second position of the copper atoms in the channels of the CuyMo6X8 compounds. This new position reinforces the interaction with the Mo-6 cluster, and may be able to involve new remarkable physical properties as thermoelectric properties. (C) 2002 Elsevier Science (USA). All rights reserved. [References: 16]