Characterization of Bi{sub 5}Nb{sub 3}O{sub 15} by refinement of neutron diffraction pattern, acid treatment and reaction of the acid-treated product with n-alkylamines
- Department of Applied Chemistry, School of Science and Engineering, Waseda University, 3-4-1, Ohkubo, Shinjuku-ku, Tokyo 169-8555 (Japan)
- Department of Research Interdisciplinary Graduate School of Medicine and Engineering, University of Yamanashi, Miyamae-cho 7, Kofu 400-8511 (Japan)
The structure of Bi{sub 5}Nb{sub 3}O{sub 15} was investigated by refinement of the powder neutron diffraction pattern as well as by structural change through acid treatment and subsequent treatments of an acid-treated product with n-alkylamines. Rietveld refinement suggests that Bi{sub 5}Nb{sub 3}O{sub 15} adopts a mixed-layer Aurivillius-related phase structure, [Bi{sub 2}O{sub 2}]+[NbO{sub 4}]+[Bi{sub 2}O{sub 2}]+[BiNb{sub 2}O{sub 7}] [Pnc2 (space group No. 30)] with a=2.1011(4), b=0.5473(1) and c=0.5463(1) nm. After the acid treatment of Bi{sub 5}Nb{sub 3}O{sub 15} with 3 mol/L HCl, a new reflection (at 2.25 nm after drying at room temperature or at 1.89 nm after drying at 120 deg. C) appeared in the X-ray diffraction (XRD) pattern in addition to the reflections due to Bi{sub 5}Nb{sub 3}O{sub 15}. Upon acid treatment, a part of the Bi ions were lost and essentially no Nb ions were dissolved during acid treatment to give a Bi/Nb molar ratio of 1.4. The TG curves of the acid-treated product showed mass loss (ca. 4 mass%) in the range of 300-600 deg. C. It was also demonstrated that the particle shapes did not change upon acid treatment. The reaction of the acid-treated product (after drying at room temperature) with n-alkylamines led to a shift of the newly appearing reflection to a lower angle, and the d-value of the low-angle reflection increased linearly in accordance with the increment of the number of carbon atoms in n-alkylamines. These results indicate that the [Bi{sub 2}O{sub 2}] sheet in Bi{sub 5}Nb{sub 3}O{sub 15} was partially leached by acid treatment to form a layered compound H{sub 4}BiNb{sub 3}O{sub 11}.xH{sub 2}O, capable of accommodating n-alkylamines in the interlayer space, and its anhydrous form, H{sub 4}BiNb{sub 3}O{sub 11}, upon drying. Based on the variation in the interlayer distance upon intercalation of n-alkylamines into the acid-treated product, the structure of the acid-treated product can be suggested to comprise alternately stacked protonated [BiNb{sub 2}O{sub 7}] and [NbO{sub 4}] sheets, a result consistent with the Rietveld refinement of Bi{sub 5}Nb{sub 3}O{sub 15}. - Graphical abstract: Crystal structure of Bi{sub 5}Nb{sub 3}O{sub 15} is investigated by refinement of neutron diffraction pattern as well as by structural change through acid treatment of Bi{sub 5}Nb{sub 3}O{sub 15} and subsequent treatment of an acid-treated product with n-alkylamine.
- OSTI ID:
- 21043836
- Journal Information:
- Journal of Solid State Chemistry, Vol. 180, Issue 9; Other Information: DOI: 10.1016/j.jssc.2007.05.017; PII: S0022-4596(07)00200-9; Copyright (c) 2007 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
Similar Records
Single- and Double-Site Substitutions in Mixed-Metal Oxides: Adjusting the Band Edges Toward the Water Redox Couples
BiNb{sub 3}O{sub 9}, a metastable perovskite phase with Bi/vacancy ordering: Crystal structure and dielectric properties