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Synthesis, Crystal and Electronic Structure of a Samarium Carbochromate(III), Sm 2 [Cr 2 C 3 ]
Author(s) -
Davaasuren Bambar,
Dashjav Enkhtsetseg,
Kerkau Alexander,
Kreiner Guido,
Schnelle Walter,
Wagner Frank R.,
Kniep Rüdiger
Publication year - 2009
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.200900214
Subject(s) - samarium , crystal structure , crystallography , chromium , rietveld refinement , chemistry , magnetic susceptibility , materials science , inorganic chemistry , metallurgy
Carbochromates RE 2 [Cr 2 C 3 ] ( RE = Y, Gd – Lu) form an isotypic series crystallizing with the Ho 2 [Cr 2 C 3 ] structure type. Here, we report on a new member of this series: Sm 2 [Cr 2 C 3 ] ( C 2/ m , a = 1054.4(1) pm, b = 346.8(1) pm, c = 568.9(1) pm, β = 105.57(1)°, V = 200.4(1) ·10 6 nm 3 , Z = 2). The samarium compound was prepared by high temperature reaction of a mixture of the elements in nominal molar amounts. Rietveld refinements of the X‐ray powder diffraction data converged to residuals of R p = 0.007 and R w p = 0.010. In the crystal structure, chromium is tetrahedrally coordinated by four carbon ligands forming polyanionic layers ∞ 2 [(Cr 2 C 3 ) 6– ], alternating with layers of Sm 3+ ions along [100]. Sm 2 [Cr 2 C 3 ] was further characterized by metallographic analysis, WDXS and magnetic susceptibility data. Chemical bonding analyses using the COHP method on the basis of LMTO‐ASA calculations justify Sm 2 [Cr 2 C 3 ] to be best described as a carbochromate(III). The stability of the Ho 2 [Cr 2 C 3 ] structure type for Sm 2 [Cr 2 C 3 ] in comparison with the closely related Er 2 [Mo 2 C 3 ] and Pr 2 [Mo 2 C 3 ] structure type structure is confirmed by total energy calculations using the PAW method.