Hydrothermal Synthesis and Crystal Structure of a New BariumVanadium Bronze Ba1+xV8O21 with a Tunnel Structure

✍ Scribed by Yoshio Oka; Takeshi Yao; Naoichi Yamamoto

• Publisher: Elsevier Science
• Year: 2000
• Tongue: English
• Weight: 225 KB
• Volume: 150
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1999.8598

✦ Synopsis

A barium vanadium bronze Ba 1؉x V 8 O 21 has been hydrothermally synthesized and structurally characterized. Hydrothermal treatment of a suspension of VO 2 powders in Ba(NO 3 ) 2 solution at 3503C yielded a 5brous brown compound having nonstoichiometric composition Ba 1؉x V 8 O 21 (x ‫؍‬ 0.13). Single-crystal X-ray di4ractometry revealed the monoclinic system C2/m with a ‫؍‬ 15.144(6), b ‫؍‬ 3.596(4), c ‫؍‬ 14.972(3) A > , ‫؍‬ 90.08(3)3, and Z ‫؍‬ 2, with the re5nement based on 2021 re6ections with I' '3 (I ) converged to R ‫؍‬ 0.054 and R w ‫؍‬ 0.046. A new tunneltype bronze structure was disclosed in which VO 6 octahedra and VO 5 trigonal bipyramids form a V+O framework with a tunnel cavity running along [010]. The Ba atom partially occupies the tunnel site with more than half occupancy of 56.6%, which causes displacement of the Ba atom and further displacement of V and O atoms along the tunnel axis. Ba 1؉x V 8 O 21 is the 5rst tunnel-type barium vanadium bronze whose structure has been fully determined.