Synthesis, crystal structure, spectrum properties, and electronic structure of a new barium aluminoborate, Ba8[(Al6IV)(Al2IV)(Al2V)B12IIIO41]
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- 作者：Xuean ; Chena ; ; xueanchen@bjut.edu.cn ; Zhipeng ; Chua ; Xinan ; Changa ; Hegui ; Zanga ; Weiqiang ; Xiaob
- 关键词：Ba8Al10B12O41 ; Borate ; Crystal structure ; Band structure
- 刊名：Journal of Alloys and Compounds
- 出版年：2012
- 出版时间：15 January 2012
- 年：2012
- 卷：511
- 期：1
- 页码：74-80
- 全文大小：516 K
文摘
A new barium aluminoborate, Ba8[(Al6IV)(Al2IV)(Al2V)B12IIIO41]?/sub>, has been prepared by solid state reaction method below 770 ¡ãC, with adding Bi2O3 as a flux. Single-crystal XRD analysis showed that it crystallizes in the triclinic space group with a = 9.2437(11) ?, b = 9.8100(12) ?, c = 11.0830(14) ?, ¦Á = 76.130(10)¡ã, ¦Â = 73.550(9)¡ã, ¦Ã = 77.990(10)¡ã, Z = 1. The crystal structure contains Latin capital H letter shaped Al6O1920?/sup> groups built up from six corner-sharing AlO4 tetrahedra. The Al6O1920?/sup> groups, AlO4 tetrahedra, AlO5 trigonal bipyramids, and BO3 triangles are linked to form a two-dimensional layer by sharing O vertices. The layers are stacked along the c-axis, with the interlayer void spaces and intralayer open channels occupied by Ba2+ cations to balance charge. The IR spectrum further confirmed the presence of BO3 groups. UV¨CVis diffuse reflectance spectrum showed a band gap of about 3.10 eV. Solid-state fluorescence spectrum exhibited a broad emission band at around 430 nm. Band structure calculations indicated that it is a direct band material with the calculated band gap (3.25 eV) close to the observed one.