Synthesis and structural study of hexagonal perovskites in the Ba{sub 5}Ta{sub 4}O{sub 15}-MZrO{sub 3} (M = Ba, Sr) system
- Moscow State Univ. (Russian Federation). Dept. of Chemistry
- Univ. of Antwerp (Belgium)
New cation-deficient perovskite-like oxides Ba{sub 5}MTa{sub 4}ZrO{sub 18} and Ba{sub 5}MTa{sub 4}Zr{sub 2}O{sub 21} (M = Ba, Sr) were synthesized and studied by X-ray diffraction, electron diffraction, and high-resolution electron microscopy (HREM). The Ba{sub 5}SrTa{sub 4}ZrO{sub 18} (space group R{bar 3}m, (hcccch), a = 5.80162(8) {angstrom}, c = 42.5043(8) {angstrom}, R{sub I} = 0.039, R{sub p} = 0.082) and Ba{sub 5}Sr{sub 2}Ta{sub 4}ZrO{sub 21} (space group R{bar 3}m, (hccccch){sub 3}, a = 5.7998(1) {angstrom}, c = 49.595(1) {angstrom}, R{sub I} = 0.033, R{sub p} = 0.080) crystal structures were refined from X-ray powder diffraction data. The results of structure refinements were confirmed by HREM observations. The formation of the Ba{sub 5}Sr{sub 3}Ta{sub 4}Zr{sub 3}O{sub 24} compound was revealed and the structure of this compound was deduced from HREM (space group P{bar 3}m1, hcccccch, a {approx} 5.8 {angstrom}, c {approx} 18.9 {angstrom}). All these compounds belong to the A{sub n}B{sub n{minus}1}O{sub 3n} homologous series of cation-deficient hexagonal perovskite-like oxides with n = 6, 7, and 8 and may be formally described as intergrowth structures with alternating Ba{sub 5}Ta{sub 4}O{sub 15}-type and Ba(Sr)ZrO{sub 3}-type structural blocks along the c axis.
- OSTI ID:
- 329155
- Journal Information:
- Journal of Solid State Chemistry, Vol. 141, Issue 2; Other Information: PBD: Dec 1998
- Country of Publication:
- United States
- Language:
- English
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