A Monophosphate Molybdenum Bronze Built up from ReO3-Type Slabs: Ag0.7Mo3O7(PO4)

✍ Scribed by S. Ledain; A. Leclaire; M.M. Borel; J. Provost; B. Raveau

• Book ID: 102606025
• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 356 KB
• Volume: 140
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1998.7874

✦ Synopsis

A monophosphate molybdenum bronze Ag 2.8 (PO 2 ) 4 (MoO 3 ) 12 has been synthesized for the first time. This monoclinic bronze (a ‫؍‬ 23.857(3) A s s , b ‫؍‬ 5.2990(6) A s s , c ‫؍‬ 6.5659(4) A s s , ‫؍‬ 93.950(6)°°), represents the m ‫؍‬ 6 member of the A x (PO 2 ) 4 (MO 3 ) 2m family (M ‫؍‬ W, Mo). Its structure, which consists of ReO 3 -type slabs interconnected with monophosphate groups, is very similar to those of the m ‫؍‬ 6 members K x (PO 2 ) 4 (WO 3 ) 12 and Mo 4 O 11 , forming hexagonal tunnels where the Ag ؉ cations are located. The distribtion of Ag ؉ in the tunnels is however different from that of K ؉ in the phosphate tungsten bronze: two sites are partially occupied close to the walls of the tunnels so that Ag ؉ exhibits a ninefold and a tetrahedral coordination. The resistivity measurements, although performed on polyphasic samples, clearly show a semiconducting behavior. The possibility of charge density wave properties is considered.