New Quaternary Chalcogenides BaLnMQ3 (Ln = Rare Earth or Sc; M = Cu, Ag; Q= S, Se): II. Structure and Property Variation vs Rare-Earth Element

✍ Scribed by Ping Wu; Amy E. Christuk; James A. Ibers

• Publisher: Elsevier Science
• Year: 1994
• Tongue: English
• Weight: 403 KB
• Volume: 110
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1994.1177

✦ Synopsis

Some new quaternary compounds of the type (\mathrm{Ba} L n M Q_{3}(L n=) rare earth or (\mathrm{Sc} ; M=\mathrm{Cu}, \mathrm{Ag} ; Q=\mathrm{S}, \mathrm{Se}) ) have been synthesized by the reaction of the constituent binary chalcogenides and elements at (1000^{\circ} \mathrm{C}). The crystal structures of two of these compounds have been determined by single-crystal (\mathrm{X})-ray diffraction techniques and are isostructural. Crystal data: (\mathrm{BaErCuS}{3})-space group (D{2 h}^{17}-C m c m, M=464.32, Z=4, a=3.987(1), b=13.377(3)), (c=10.101(2) \AA(T=115 \mathrm{~K}), V=538.7(4) \AA^{3}, R_{w}\left(F^{2}\right)=0.095) for 848 observations and 24 variables, (R(F)=0.037) for 840 observations having (F_{0}^{2}>2 \sigma\left(F_{0}^{2}\right)); BaYAgSe (e_{3})-space group (D_{2 h}^{17}-\mathrm{Cmcm}, M=571.0, Z=4, a=4.239(1), b=14.030(2)), (c=10.636(2) \AA(T=115 \mathrm{~K}), V=632.6(2) \AA^{3}, R_{w}\left(F^{2}\right)=0.057) for 645 observations and 24 variables, (R(F)=0.023) for 595 observations having (F_{o}^{2}>2 \sigma\left(F_{o}^{2}\right)). These two compounds adopt the layered (\mathrm{KZrCuS}{3}) structure type. The layers, which are separated by (\mathrm{Ba}^{2+}) ions, consist of edge-sharing octahedral chains and cornersharing tetrahedral chains. The other compounds synthesized crystallize either with this same structure or with that of (\beta) - (\mathrm{BaLaCuSe}{3}), a slightly distorted variation, which is isostructural with (\mathrm{Eu}{2} \mathrm{CuS}{3}). The diffuse reflective UV-visible spectra of several of these compounds have been measured. From magnetic susceptibility measurements, both (\mathrm{BaNdCuS}{3}) and (\mathrm{BaGdCuS}{3}) show Curie-Weiss behavior, whereas (\mathrm{BaCeCuS}{3}) and (\mathrm{BaCeCuSe}{3}) show in addition temperature-independent paramagnetism. 1994 Academic Press, Inc.