Crystal structure of Ca12Al14O32Cl2 and luminescence properties of Ca12Al14O32Cl2:Eu2+
Crystal structure of Ca12Al14O32Cl2 and luminescence properties of Ca12Al14O32Cl2:Eu2+
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DOI：
10.1016/j.jssc.2007.11.002
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发表时间：
2008
影响因子：
3.3
通讯作者：
T. Iwata;Masahide Haniuda;K. Fukuda
中科院分区：
文献类型：
--
作者：
T. Iwata;Masahide Haniuda;K. Fukuda
用Rietveld方法从实验室X射线粉末衍射数据(Cuk{α}{sub1})确定了Ca{sub12}Al{sub14}O{sub32}Cl{sub2}的晶体结构，并给出了各向异性位移参数。晶体结构为立方结构(空间群I4-bar 3D，Z=2)，晶格尺寸a=1.200950(5)nm，V=1.73211(1)nm{sup 3}。由Rietveld法计算的可靠性指标为：R{subWp}=8.48%(S=1.2 1)，R{subp}=6.0 5%，R{subB}=1.2 7%，R{subF}=1.0 1%。通过三维电子密度分布验证了结构模型的有效性，并利用基于最大熵方法的图案拟合(MPF)尽可能地降低了结构偏差。由MPF计算的可靠性指标分别为R{subB}=0.75%和R{subF}=0.56%。在结构模型中，有1个Ca位、2个Al位、2个O位和1个Cl位。该化合物与Ca{sub12}Al{sub10.6}Si{sub3.4}O{sub32}Cl{sub5.4}同构。制备了掺杂Eu的样品Casub12}Alsub14}O{sub32}Clsub2}：Eu{sup2+}，并对其光致发光性能进行了表征。激发光谱由约268和324 nm处的两个宽带组成。当激发波长为324 nm时，发射光谱产生了蓝光，峰值位于442 nm。-图形摘要：Ca{sub12}Al{sub14}O{sub32}Cl{sub2}晶体结构的一部分，显示八元AlO{sub4}环和Ca-Cl-Ca单元。
The crystal structure of Ca{sub 12}Al{sub 14}O{sub 32}Cl{sub 2} was determined from laboratory X-ray powder diffraction data (CuK{alpha}{sub 1}) using the Rietveld method, with the anisotropic displacement parameters being assigned for all atoms. The crystal structure is cubic (space group I4-bar 3d, Z=2) with lattice dimensions a=1.200950(5) nm and V=1.73211(1) nm{sup 3}. The reliability indices calculated from the Rietveld method were R{sub wp}=8.48% (S=1.21), R{sub p}=6.05%, R{sub B}=1.27% and R{sub F}=1.01%. The validity of the structural model was verified by the three-dimensional electron density distribution, the structural bias of which was reduced as much as possible using the maximum-entropy methods-based pattern fitting (MPF). The reliability indices calculated from the MPF were R{sub B}=0.75% and R{sub F}=0.56%. In the structural model there are one Ca site, two Al sites, two O sites and one Cl site. This compound is isomorphous with Ca{sub 12}Al{sub 10.6}Si{sub 3.4}O{sub 32}Cl{sub 5.4}. Europium-doped sample Ca{sub 12}Al{sub 14}O{sub 32}Cl{sub 2}:Eu{sup 2+} was prepared and the photoluminescence properties were presented. The excitation spectrum consisted of two wide bands, which were located at about 268 and 324 nm. The emission spectrum, when excited at 324 nm, resulted in indigo light with a peak at about 442 nm. - Graphical abstract: A portion of the crystal structure of Ca{sub 12}Al{sub 14}O{sub 32}Cl{sub 2} showing eight-membered AlO{sub 4} rings and Ca-Cl-Ca unit.