Crystal structure study of new lanthanide silicates with silico-carnotite structure
Crystal structure study of new lanthanide silicates with silico-carnotite structure
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DOI：
10.1016/j.jssc.2012.05.012
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发表时间：
2012-10
影响因子：
3.3
通讯作者：
F. Piccinelli;A. Lausi;A. Speghini;Marco Bettinelli
中科院分区：
文献类型：
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作者：
F. Piccinelli;A. Lausi;A. Speghini;Marco Bettinelli
用粉末X射线衍射法测定了新的稀土硅酸盐化合物（Ca 3Eu 2Si 3 O 12，Ca 3Gd 2Si 3 O 12，Ca 3Dy 2Si 3 O 12，Ca 3Er 2Si 3 O 12和Ca 3Lu 2Si 3 O 12）的晶体结构。从Rietveld细化计算收集的粉末图案，我们观察到不同的分布的稀土离子的三个可用的晶体网站，其特征在于不同的配位数，这取决于稀土离子的离子半径。对大于Eu ~（3+）的镧系离子的硅-钒矿结构不稳定的原因进行了推测。此外，为了检测晶体相变，已经收集了Ca 3Eu 2Si 3 O 12和Ca 3Sm 2Si 3 O 12样品的粉末图案作为温度的函数（RT-1000°C范围），但是没有观察到相变。
The crystal structures of new rare earth-based silicate compounds (Ca3Eu2Si3O12, Ca3Gd2Si3O12, Ca3Dy2Si3O12, Ca3Er2Si3O12and Ca3Lu2Si3O12) have been determined using powder X-ray diffraction. From Rietveld refinement calculations on the collected powder patterns we observe a different distribution of the rare earth ions on the three available crystal sites characterized by different coordination numbers, depending on the ionic radius of the rare earth ion. The reasons of the instability of the silico-carnotite structure for lanthanide ions larger than Eu3+have been deduced. In addition, in order to detect crystal phase transitions, the powder patterns of Ca3Eu2Si3O12and Ca3Sm2Si3O12samples have been collected as a function of the temperature (RT-1000°C range), but no phase transitions have been observed.