Ternary lanthanum sulfide selenides {alpha}-LaS{sub 2-x}Se{sub x} (0<x<2) with mixed dichalcogenide anions X{sub 2}{sup 2-} (X=S, Se)

Journal Article · Sun Jan 15 00:00:00 EST 2012 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2011.10.039· OSTI ID:21612857

Bartsch, Christian ^[1]; Doert, Thomas ^[1]

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1. Department of Chemistry and Food Chemistry, Technische Universitaet Dresden, D-01062 Dresden (Germany)

Mixed lanthanum sulfide selenides LaS{sub 2-x}Se{sub x} (0<x<2) were obtained by metathesis reactions starting from anhydrous lanthanum chloride and alkali metal polychalcogenides. The LaS{sub 2-x}Se{sub x} compounds crystallize in space group P2{sub 1}/a, no. 14, and adopt the {alpha}-LnS{sub 2} (Ln=Y, La-Lu) structure type with a pronounced site preference for the chalcogen atoms. The mixed chalcogenides form a complete miscible series with lattice parameters a=820-849 pm, b=413-425 pm and c=822-857 pm ({beta} Almost-Equal-To 90 Degree-Sign) following Vegard's rule. Raman signals indicate the presence of mixed X{sub 2}{sup 2-} dianions, a species rarely evidenced in literature, besides the well known anions S{sub 2}{sup 2-} and Se{sub 2}{sup 2-}. The band gaps of the LaS{sub 2-x}Se{sub x} compounds, determined by optical spectroscopy, decrease nearly linearly with increasing amount of selenium. - Graphical abstract: Raman spectra and site occupancies in the structures of selected lanthanum sulfide selenides. Highlights: Black-Right-Pointing-Pointer Vegard series of mixed lanthanum sulfide selenides LaS{sub 2-x}Se{sub x} (0<x<2). Black-Right-Pointing-Pointer Pronounced site ordering of chalcogen positions. Black-Right-Pointing-Pointer Optical band gaps decrease with Se content. Black-Right-Pointing-Pointer Raman measurements evidence mixed X{sub 2}{sup 2-} dimeric anions.

• OSTI ID: 21612857
• Journal Information: Journal of Solid State Chemistry, Vol. 185; Other Information: DOI: 10.1016/j.jssc.2011.10.039; PII: S0022-4596(11)00581-0; Copyright (c) 2011 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALKALI METALS
ANIONS
LANTHANUM CHLORIDES
LANTHANUM SULFIDES
LATTICE PARAMETERS
MONOCLINIC LATTICES
RAMAN SPECTRA
RARE EARTHS
SELENIDES
SELENIUM
SIGNALS
SPACE GROUPS
SPECTROSCOPY
CHALCOGENIDES
CHARGED PARTICLES
CHLORIDES
CHLORINE COMPOUNDS
CRYSTAL LATTICES
CRYSTAL STRUCTURE
ELEMENTS
HALIDES
HALOGEN COMPOUNDS
IONS
LANTHANUM COMPOUNDS
LANTHANUM HALIDES
METALS
RARE EARTH COMPOUNDS
SELENIUM COMPOUNDS
SEMIMETALS
SPECTRA
SULFIDES
SULFUR COMPOUNDS
SYMMETRY GROUPS