Synthesis and Structure of a New Ternary Silver-Rich Sulfide BaAg8S5

✍ Scribed by Catherine E. Check; Chong Zheng; Jianhua Zhang; Bogdan Dabrowski

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 426 KB
• Volume: 144
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1999.8188

✦ Synopsis

A new ternary silver-rich sul5de, BaAg 8 S 5 , was synthesized. This solid-state compound crystallizes in the monoclinic, centrosymmetric space group P2 1 /m with a ‫؍‬ 7.6720(2) A s , b ‫؍‬ 17.6660(4) A s , c ‫؍‬ 8.9370(2) A s , ‫؍‬ 107.890(1)3, Z ‫؍‬ 4, and V ‫؍‬ 1152.70(5) A s 3 . The re5nement results are R1 ‫؍‬ 0.0490 and wR2 ‫؍‬ 0.1136 for I > 2 (I) using 2552 re6ections and 137 parameters. As in the binary -Ag 2 S and -Ag 2 S solids, the coordination geometry of both Ag and S is complex. However, if only the bonding of Ag to S is concerned, the arrangement is simple. Ag of the 5rst type is connected to two S atoms in both linear and bent fashions. Ag of the second type is coordinated to three S atoms in a pyramidal shape. The structure can be viewed as a threedimensional network formed by Ag and S atoms with Ba atoms occupying channels parallel to the c axis. Theoretical analysis using the extended HuK ckel method indicates that the solid should be a semiconductor.