α-,β-Pb4B2O7 andα-,β-Pb4B6O13:Polymorphism drives changes in structure and performance  

α-,β-Pb4B2O7和α-,β-Pb4B6O13:多态性驱动结构和性能变化

作　　者：Chunmei Huang Fangfang Zhang Shichao Cheng Zhihua Yang Shilie Pan 黄春梅;张方方;程世超;杨志华;潘世烈(CAS Key Laboratory of Functional Materials and Devices for Special Environments,Xinjiang Technical Institute of Physics&Chemistry,CAS,Xinjiang Key Laboratory of Electronic Information Materials and Devices,Urumqi 830011,China;Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]CAS Key Laboratory of Functional Materials and Devices for Special Environments,Xinjiang Technical Institute of Physics&Chemistry,CAS,Xinjiang Key Laboratory of Electronic Information Materials and Devices,Urumqi 830011,China [2]Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science China Materials》2020年第5期806-815,共10页中国科学（材料科学（英文版）

基　　金：supported by the Key Research Project of Frontier Science of CAS(QYZDB-SSW-JSC049);the National Natural Science Foundation of China(61875229,61835014 and 61922084);the National Key Research Project(2016YFB0402104);the Youth Innovation Promotion Association of CAS(2012305).

摘　　要：Introducing Pb2+cations with lone pair electrons in borates is efficient to form multiple crystalline forms.Here,we report two new compounds,α-Pb4B2O7 andβ-Pb4B6O13,which exhibit different crystal forms from the previously reported lead borates,β-Pb4B2O7 andα-Pb4B6O13,respectively.Two sets of polymorphs:α-,β-Pb4B2O7 andα-,β-Pb4B6O13,exhibit completely different crystal structures and diverse optical properties.Thermal gravimetric and differential scanning calorimetry(TG-DSC)and variable-temperature powder X-ray diffraction(XRD)analyses were performed to study their thermodynamic stabilities.Structure-property relationships were discussed through first-principles calculation.Notably,the new phases,α-Pb4B2O7 andβ-Pb4B6O13,have larger birefringence than their corresponding polymorphs due to the rearrangement of the functional groups in their structures.在硼酸盐中引入带孤对电子的Pb2+离子可以有效地形成多种结晶形态.本文报道了两个新的结构,α-Pb4B2O7和β-Pb4B6O13.这两个结构与已经报道的两例硼酸盐β-Pb4B2O7和α-Pb4B6O13具有不同的晶体形式.两组多形体:α-,β-Pb4B2O7和α-,β-Pb4B6O13,分别具有完全不同的晶体结构和光学性质.采用热重-差示扫描量热法(TG-DSC)和变温粉末X射线衍射(XRD)分析对α-Pb4B2O7和β-Pb4B6O13的热力学稳定性进行了研究.通过第一性原理计算讨论了结构与性质的关系.值得注意的是,由于结构中功能基团的重组,两个新的相,α-Pb4B2O7和β-Pb4B6O13,具有比与之对应的多形体较大的双折射.

关 键 词：BORATE POLYMORPHISM BIREFRINGENCE FIRST-PRINCIPLES CALCULATION 

分 类 号：O614.433[理学—无机化学]