Synthesis, Structure, Electrical Conductivity, and Band Structure of the Rare-Earth Copper Oxychalcogenide La5Cu6O4S7

✍ Scribed by Fu Qiang Huang; Paul Brazis; Carl R. Kannewurf; James A. Ibers

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 269 KB
• Volume: 155
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2000.8926

✦ Synopsis

a new structure type in a cell of dimensions a ‫؍‬ 5.667(1), b ‫؍‬ 15.666(3), c ‫؍‬ 17.534(3) A > with four formula units in space group D 28 2h -Imma of the orthorhombic system at T ‫؍‬ 153 K. The structure comprises [Cu 2 S 2 ] anti6uorite-like and [La 10 S 2 O 8 ] 6uorite-like layers, and these two kinds of layers stack in turn along the [001] direction. The La atom is coordinated by a distorted square antiprism of four O and four S atoms, and the Cu atom is coordinated by a tetrahedron of four S atoms. The Cu atom in the [Cu 2 S 2 ] layer is bonded to neighboring Cu atoms; the Cu}Cu distances vary from 2.5864(7) to 2.965(1) A > . The average oxidation state of the Cu atoms is ؉7/6. La 5 Cu 6 O 4 S 7 is metallic in the [100] direction, consistent with the results of extended HuK ckel band structure calculation.