New Ternary Lanthanide Transition-Metal Tellurides: Dy6MTe2, M=Fe, Co, Ni

The isotypic title compounds together with R6CoTe2 for R=Y, La have been synthesized in Ta containers at high temperature and their lattice parameters refined from Guinier X-ray powder diffraction data. The structure of this family has been detailed in space group P 2m (Z=1) by single-crystal X-ray diffraction data for the case of Dy6FeTe2 (a=8.236(3) ?, c=4.0107(2) ?, 23°C, R(F)/Rw=3.6/3.8%). The overall structure is of the Zr6CoAl2 type, an ordered derivative of the Fe2P type. Extended Hückel calculations help to interpret the stabilization of this structure by iron or electron-richer elements. Strong Dy-Fe interactions in more 1D chains are a noteworthy feature.