skip to main content

SciTech ConnectSciTech Connect

Title: Rare-earth transition-metal indium sulphides RE{sub 3}FeInS{sub 7} (RE=La–Pr), RE{sub 3}CoInS{sub 7} (RE=La, Ce), and La{sub 3}NiInS{sub 7}

Six quaternary rare-earth-containing sulphides RE{sub 3}MInS{sub 7} (M=Fe, Co, Ni) have been prepared by reactions of the elements at 1050–1150 °C. They are the first examples of chalcogenides RE{sub 3}MM'Ch{sub 7} adopting related La{sub 3}CuSiS{sub 7}- or ordered Ce{sub 3}Al{sub 1.67}S{sub 7}-type structures in which the M' component is indium. They crystallize in the noncentrosymmetric hexagonal space group P6{sub 3} with Z=2 and cell parameters in the ranges of a=9.95–10.15 Å and c=6.25–6.29 Å for RE{sub 3}FeInS{sub 7} (RE=La–Pr), RE{sub 3}CoInS{sub 7} (RE=La, Ce), and La{sub 3}NiInS{sub 7}. The crystal structure consists of parallel chains of face-sharing M-centred octahedra and stacks of In-centred tetrahedra, all pointing in the same polar direction, with seven-coordinate La atoms in the intervening spaces. X-ray photoelectron spectra support the valence assignments implied by the formulation (RE{sup 3+}){sub 3}(M{sup 2+})(In{sup 3+})(S{sup 2−}){sub 7}. Magnetic measurements are suggestive of antiferromagnetic coupling between the M moments. Band structure calculations reveal that a band gap of 0.25 eV is present in La{sub 3}FeInS{sub 7}, whereas the increased electron count in La{sub 3}CoInS{sub 7} and La{sub 3}NiInS{sub 7} causes the Fermi level to cut narrow bands. - Graphical abstract: RE{sub 3}MInS{sub 7} (M=Fe, Co, Ni) consists of chains of face-sharingmore » M-centred octahedra and stacks of In-centred tetrahedra. - Highlights: • Six members of noncentrosymmetric sulphide series RE{sub 3}MInS{sub 7} have been prepared. • They are the first examples of chalcogenides RE{sub 3}MM'Ch{sub 7} with In atoms in M' site. • X-ray photoelectron spectra support the formulation (RE{sup 3+}){sub 3}(M{sup 2+})(In{sup 3+})(S{sup 2−}){sub 7}. • Band structure calculations suggest semiconducting or metallic behaviour.« less
Authors:
; ;
Publication Date:
OSTI Identifier:
22309069
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Solid State Chemistry; Journal Volume: 208; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANTIFERROMAGNETISM; ELECTRONIC STRUCTURE; FERMI LEVEL; HEXAGONAL LATTICES; INDIUM; INDIUM IONS; MAGNETIC PROPERTIES; RARE EARTHS; SPACE GROUPS; SULFIDES; TRANSITION ELEMENTS; X-RAY PHOTOELECTRON SPECTROSCOPY