重稀土氟氧化物单晶高压合成及结构解析  

High-pressure synthesis and structural analysis of heavy rare-earth oxyfluorides single crystals

作　　者：张帅 王春垚 韦春婉 许金贵 张东舟 周丽 周文戈[1] ZHANG Shuai;WANG Chun-yao;WEI Chun-wan;XU Jin-gui;ZHANG Dong-zhou;ZHOU Li;ZHOU Wen-ge(Key Laboratory of High-temperature and High-pressure Study of the Earth's Interior,Institute of Geochemistry,Chinese Academy of Sciences,Guiyang 550081,China;University of Chinese Academy of Sciences,Beijing 100049,China;Laboratory of Orogenic Belts and Crustal Evolution,School of Earth and Space Sciences,Peking University,Beijing 100871,China;Hawaii Institute of Geophysics and Planetology,School of Ocean and Earth Science and Technology,University of Hawaii at Manoa,Honolulu,HI 96822,USA;School of Geography and Environmental Science,Guizhou Normal University,Guiyang 550025,China)

机构地区：[1]中国科学院地球化学研究所地球内部物质高温高压院重点实验室,贵州贵阳550081 [2]中国科学院大学,北京100049 [3]北京大学地球与空间科学学院,造山带与地壳演化重点实验室,北京100871 [4]夏威夷大学夏威夷大学马诺阿分校地球物理与行星研究所,美国檀香山HI96822 [5]贵州师范大学地理与环境科学学院,贵州贵阳550025

出　　处：《矿物学报》2022年第6期775-784,共10页Acta Mineralogica Sinica

基　　金：国家自然科学基金项目(编号:91962108,41773058)。

摘　　要：利用高温高压技术合成了非化学式计量比HREEO_(1-x)F_(1+2x)型重稀土氟氧化物的单晶(HREE=Gd,Ho,Tm,Yb;x=0.0269、0.0066、0.0502、0.1078):GdO_(0.9731±0.0049)F_(1.0538±0.0099)、HoO_(0.9934±0.0054)F_(1.0132±0.0109)、TmO_(0.9498±0.0146)F_(1.1005±0.0292)、YbO_(0.8922±0.0028)F_(1.2157±0.0054),并利用拉曼光谱及单晶X射线衍射(SCXRD)测定了它们的拉曼光谱特征和晶体结构。拉曼光谱结果显示,合成的非化学式计量比重稀土氟氧化物的拉曼谱整体相似,都有4个强度较高的拉曼特征峰,随着原子序数的增加拉曼位移呈现规律性的变化。SCXRD结果显示,合成的非化学式计量比重稀土氟氧化物均属于正交晶系,其中,GdO_(0.9731)F_(1.0538)为Pbcm空间群,而后3个属于Aem2空间群。其中GdO_(0.9731)F_(1.0538)的晶胞参数为a=0.5334(3)nm,b=0.5474(1)nm,c=3.2786(2)nm;HoO_(0.9934)F_(1.0132)晶胞参数为a=0.5438(1)nm,b=3.8661(1)nm,c=0.5536(1)nm;TmO_(0.9498)F_(1.1005)的晶胞参数为a=0.5369(1)nm,b=3.8340(1)nm,c=0.5492(1)nm;YbO_(0.8922)F_(1.2157)的晶胞参数为a=0.5349(1)nm,b=4.9006(2)nm,c=0.5469(1)nm。晶体单胞是由n个类萤石结构的亚晶胞沿b或c轴方向堆叠而成,其中有部分亚晶胞被O^(2-)离子替代或被F^(-)、O^(2-)共同占据,形成6、7或8配位的类萤石亚晶胞结构,6和7配位的亚晶胞会发生结构上的畸变而8配位亚晶胞与萤石结构的亚晶胞基本一致。We have synthesized single crystals of heavy rare-earth oxyfluorides with the non-stoichiometric ratios of HREEO_(1-x)F_(1+2x)(HREE=Gd,Ho,Tm,Yb;x=0.0269,0.0066,0.0502,0.1078),such as GdO_(0.9731±0.0049)F_(1.0538±0.0099),HoO_(0.9934±0.0054)F_(1.0132±0.0109),TmO_(0.9498±0.0146)F_(1.1005±0.0292),and YbO_(0.8922±0.0028)F_(1.2157±0.0054),respectively,by using high temperature high pressure techniques in this paper.Then we measured their Raman properties and crystal structures by using Raman spectroscopy and single crystal X-ray diffraction(SCXRD),respectively.The results of Raman spectrometry show that the Raman spectra of the synthesized non-stoichiometric heavy rare-earth oxyfluorides are generally similar to each other,with four high-intensity Raman characteristic peaks,and the Raman shifts changing regularly as the increase of their atomic numbers.SCXRD results show that the synthesized non-stoichiometric heavy rare-earth oxyfluorides belong to the orthorhombic system,among which the GdO_(0.9731)F_(1.0538) belongs to the Pbcm space group,and three others belong to the Aem2 space group.The unit cell parameters of a,b,and c of GdO_(0.9731)F_(1.0538) are 0.5334(3)nm,0.5474(1)nm,and 3.2786(2)nm,respectively;Those of HoO_(0.9934)F_(1.0132) are 0.5438(1)nm,3.8661(1)nm,and 0.5536(1)nm,respectively;Those of TmO_(0.9498)F_(1.1005) are 0.5369(1)nm,3.8340(1)nm,and 0.5492(1)nm,respectively;Those of YbO_(0.8922)F_(1.2157) are 0.5349(1)nm,4.9006(2)nm,and 0.5469(1)nm,respectively.The crystal unit cell is composed of n fluorite-like subunit cells stacked along the b or c axis.Some of the subunit cells are replaced by O^(2-)ions or occupied by coupled F^(-)and O^(2-)ions,forming the coordination of 6,7 or 8 fluorite-like subunit cell structures.The 6-and 7-coordination subunit cells will be structurally distorted,but the 8-coordination subunit cell is basically consistent with that of the fluorite structure.

关 键 词：非化学式计量比重稀土氟氧化物 高压单晶合成 拉曼光谱 单晶X射线衍射 晶体结构 

分 类 号：P579[天文地球—矿物学]