SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF 2 INTERCALATED LITHIUM AND SODIUM COPPER IRON SELENIDES - LICUFESE2 AND NACUFESE2

The not new phases LiCuFeSe2 and NaCuFeSe2 were prepared from the corr esponding carbonates and CuFeSe2. They crystallize as the isostructura l sulphide phases LiCuFeS2 and NaCuFeS2 in the trigonal space group P3 m1BAR (No. 164) in a layered Li2FeS2 structure type. The Se atoms form an h.c.p. array, the copper and iron atoms are statistically distribu ted in the tetrahedral sites whereas the alkali metals are placed in t he octahedral sites in the van der Waals gap.