New Quaternary Chalcogenides Ba LnMQ3 ( Ln = Rare Earth or Sc; M = Cu, Ag; Q= S, Se) : II. Structure and Property Variation vs Rare-Earth Element

• Published in: Journal of solid state chemistry Vol. 110; no. 2; pp. 337 - 344
• Main Authors: Wu, Ping, Christuk, Amy E., Ibers, James A.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 1994
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1006/jssc.1994.1177

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