Structure and Ionic Conductivity of Bi6Cr2O15, a New Structure Type Containing (Bi12O14)8n+n Columns and CrO2−4 Tetrahedra

✍ Scribed by J. Grins; S. Esmaeilzadeh; S. Hull

• Publisher: Elsevier Science
• Year: 2002
• Tongue: English
• Weight: 616 KB
• Volume: 163
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.2001.9385

✦ Synopsis

Powder samples of the Cr 6؉ -containing compound Bi 6 Cr 2 O 15 were prepared by solid state reaction of Bi 2 O 3 and Cr 2 O 3 in air at 6503C. The structure was solved and re5ned using highresolution neutron powder di4raction data in space group Ccc2, with anisotropic thermal displacement parameters a ‫؍‬ 12.30184(5), b ‫؍‬ 19.87492(7), and c ‫؍‬ 5.88162(2) A > , V ‫؍‬ 1438.0 A > 3 , and 126 variables to R F ‫؍‬ 1.8%. Bi 6 Cr 2 O 15 exhibits a new structure type that contains (Bi 12 O 14 ) 8n؉ n columns, of the kind previously found only for phases isotypic with Bi 13 Mo 4 VO 34 . Each column is surrounded by eight CrO 2؊

4 tetrahedra. The ionic conductivity of Bi 6 Cr 2 O 15 was determined by impedance measurements to be 3.5 ؋ 10 ؊5 ( cm) ؊1 at 6003C.