Dy₀.₆₄{Dy₅[Fe₂C₉]} : A complex carbide with a composite structure

Titelangaben

Davaasuren, Bambar ; Dashjav, Enkhtsetseg ; Kniep, Rüdiger ; Kreiner, Guido ; Schnelle, Walter ; Akselrud, Lev ; van Smaalen, Sander ; Wölfel, Alexander:
Dy₀.₆₄{Dy₅[Fe₂C₉]} : A complex carbide with a composite structure.
In: Journal of Solid State Chemistry. Bd. 190 (2012) . - S. 73-79.
ISSN 0022-4596
DOI: https://doi.org/10.1016/j.jssc.2012.02.008

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Abstract

The ternary carbide Dy5.64Fe2C9 has been prepared by high temperature synthesis from the elements. The compound forms as a composite structure with two partial structures, {Dy5Fe2C9} and {Dy0.64} crystallizing in space groups Pnam and Pbam, respectively. The lattice parameters a=2934.63(9) pm and b=1263.63(5) pm for the two partial structures are identical, whereas the c lattice parameters for {Dy5Fe2C9} (cH=504.14(3) pm) and {Dy0.64} (cG=1056.01(5) pm) are different. This gives rise to a modulated structure in the (3+1)D superspace group Pnam(00g) with q=cH/cG=0.4775. The refinement converged to R(F) values below 0.055 for each partial structure using harmonic and Crenel functions. The compound is a bad metallic conductor and represents a new structure type composed of Dy3+ species embedded in a matrix of discrete planar FeC(C2)2 units and edge-sharing Fe(C2)4 tetrahedra forming infinite chains Fe(C2)4/2 running along the c axis.