Systematic Study of New Rare Earth Element−Iron−Antimony Skutterudites Synthesized Using Multilayer Precursors

We have synthesized a series of stable and metastable rare earth element−iron antimonides, controlling both composition and structure using multilayer reactants. The stable rare earth iron element antimonides have the filled skutterudite structure (LaFe4P12) with a stoichiometry of 1 for the rare earth element. The metastable rare earth element−iron antimonides could be prepared with the entire sequence of rare earth elements. The lattice parameters of these metastable compounds were always larger than those of the corresponding more stable analog, and the occupancy of the rare earth element cation was found to be less than 1. Reitveld analysis of Lu1 - x Fe4Sb12 suggests that the late rare earth element compounds have a new distorted filled skutterudite structure. Structural trends are discussed in terms of their potential use as thermoelectric materials.