(Ba, Sr)3MgSi2O8 structure change caused by Ba/Sr replacement
(Ba, Sr)3MgSi2O8 structure change caused by Ba/Sr replacement
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Ba/Sr置换引起的(Ba,Sr)3MgSi2O8结构变化
DOI：
10.1017/s0885715614000803
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发表时间：
2014
影响因子：
0.5
通讯作者：
Yoshinori Yonezaki
中科院分区：
文献类型：
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作者：
Yoshinori Yonezaki
用拉曼光谱和X射线衍射测定了Ba_xSr_（3-x）MgSi_2O_8的晶体结构。该固溶体系列具有由共角SiO4四面体和MgO6八面体组成的玻璃石型层状结构。Ba2+和Sr2+离子夹在层之间。拉曼光谱学已经发现，结构对称性在x = 0.5和2.5处改变。通过Rietveld方法的结构精修已经阐明了对称性变化发生在C2（Z = 4）、P ${\bar 3}$m1（Z = 1）和P ${\bar 3}$（Z = 3）之间。它们起源于碱土金属阳离子和它们的位置空间之间的尺寸失配引起的SiO4倾斜。当x ≤ 0.5时，SiO_4每隔一个层间距发生倾斜，而当x ≥ 2.5时，所有SiO_4层间距都发生倾斜。
Crystal structure of Ba x Sr3– x MgSi2O8 has been determined by Raman spectroscopy and X-ray diffraction. The solid solution series have glaserite-type layered structures made of corner-sharing SiO4 tetrahedra and MgO6 octahedra. Ba2+ and Sr2+ ions are sandwiched in between the layers. Raman spectroscopy has found that structural symmetry changes at x = 0.5 and 2.5. Structural refinement by the Rietveld method has clarified that the symmetry changes occur among C2 (Z = 4), P ${\bar 3}$ m1 (Z = 1), and P ${\bar 3}$ (Z = 3). They originate in SiO4 tilting caused by size mismatch between alkali–earth cations and their site spaces. For x ≤ 0.5, SiO4 tilting occur every other interlayer space, whereas for x ≥ 2.5, all the SiO4 tilt.