High-Pressure Structural and Thermodynamic Properties of Cerium Orthosilicates (CeSiO 4 )
High-Pressure Structural and Thermodynamic Properties of Cerium Orthosilicates (CeSiO 4 )
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原硅酸铈 (CeSiO 4 ) 的高压结构和热力学性质
DOI：
10.1021/acs.jpcc.2c06657
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Ahmed, Sohan
中科院分区：
文献类型：
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作者：
Strzelecki, Andrew C.;Zhao, Xiaodong;Baker, Jason L.;Estevenon, Paul;Barral, Thomas;Mesbah, Adel;Popov, Dmitry;Chariton, Stella;Prakapenka, Vitali;Ahmed, Sohan
从锆石结构型（I41/amd）到白钨矿结构型（I41/a）的压力诱导相变在许多三元氧化物体系（ABO4）中是已知的。在这项工作中，我们提出了合成stetinite （CeSiO4）的第一个高压研究，结合了高达36 GPa的原位高压同步加速器粉末x射线衍射，有和没有双面激光加热，以及高达43 GPa的原位高压拉曼光谱。锆石在15 GPa时向高压低对称（HPLS）相转变，在18 GPa时向白钨矿相转变。后者来自HPLS白钨矿相，不可逆；也就是说，白钨矿在环境条件下是完全可淬的，就像其他锆石型相一样。拟合二阶Birch-Murnaghan状态方程，确定了stetinite相、HPLS相和高压白钨矿相的体积模量（K0）分别为171(5)、105(4)和221(40)GPa。该锆结构多晶体的振动模态压力导数和粒度<s:1> neisen参数与其他正硅酸盐矿物相似。由于Ce4+的离子半径较大，相对于Zr4+， stetinite具有较软的体积模量，并且在较低的压力下发生相变，这与coffinite （USiO4）的观察结果一致。
Pressure-induced phase transitions from the zircon structure-type (I41/amd) to the scheelite structure type (I41/a) are known for many ternary oxides systems (ABO4). In this work, we present the first high-pressure study on synthetic stetindite (CeSiO4) by a combination of in situ high-pressure synchrotron powder X-ray diffraction up to 36 GPa, implemented with and without dual sided laser heating, and in situ high-pressure Raman spectroscopy up to 43 GPa. Two phase transitions were identified: zircon to a high-pressure low-symmetry (HPLS) phase at 15 GPa and then to a scheelite at 18 GPa. The latter from HPLS scheelite phase was found irreversible; i.e., scheelite is fully quenchable at ambient conditions, as in other zircon-type phases. The bulk moduli (K0) of stetindite, HPLS, and high-pressure scheelite phases were determined, respectively, as 171(5), 105(4), and 221(40) GPa by fitting to a second-order Birch–Murnaghan equation of state. The pressure derivatives of vibrational modes and Grüneisen parameters of the zircon-structured polymorph are similar to those of other orthosilicate minerals. Due to the larger ionic radii of Ce4+, with respect to Zr4+, stetindite was found to possess a softer bulk modulus and undergo the phase transitions at a lower pressure than zircon (ZrSiO4), such observations are consistent with what were found in coffinite (USiO4).