Ab Initio Structure Solution of BaFeO2.8−δ, a New Polytype in the System BaFeOy (2.5≤y≤3.0) Prepared from the Oxidative Thermal Decomposition of BaFe[(CN)5NO]·3H2O
✍ Scribed by Marı́a Inés Gómez; Gabriela Lucotti; Juana A. de Morán; Pedro J. Aymonino; Silvina Pagola; Peter Stephens; Raúl E. Carbonio
- Publisher
- Elsevier Science
- Year
- 2001
- Tongue
- English
- Weight
- 474 KB
- Volume
- 160
- Category
- Article
- ISSN
- 0022-4596
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✦ Synopsis
BaFeO 2.8؊ with a crystal structure di4erent from any of those previously reported in the system BaFeO y (2.54y43.0) was prepared by a low-temperature method of synthesis, based on the oxidative thermal decomposition of BaFe[(CN) 5 NO] ' 3H 2 O. The structure was solved ab initio by high-resolution synchrotron X-ray powder di4raction and re5ned by Rietveld analysis (R P ؍ 7.78, R wp ؍ 11.3, R exp ؍ 3.76, R Bragg ؍ 6.67, 2 ؍ 9.03). The compound crystallizes in the hexagonal crystal system, space group P6 3 /mmc, Z ؍ 10, unit cell parameters a ؍ 5.77944(1), c ؍ 24.60871(6) A s . The structure consists of 10H close packed (hchch) 2 stacking of BaO n layers (eight BaO 3 layers and two oxygen-de5cient BaO 2 layers). Additional oxygen de5ciencies are randomly distributed on the h BaO 3 layers. Six iron ions occupy octahedral sites sharing faces between them along the c axis and four occupy tetrahedral sites (2 T ؉ and 2 T ؊ ) sharing faces with the octahedra and sharing corners between them.