化学学报 ›› 2022, Vol. 80 ›› Issue (2): 105-109.DOI: 10.6023/A21120550 上一篇    下一篇

研究通讯

基于分子工程的方法设计首例具有Sr2Be2B2O7 (SBBO)结构的深紫外氟碳酸盐双折射晶体AMgLi2(CO3)2F (A=K, Rb)

宋云霞a, 梁飞c, 田皓天b, 吴燕a, 罗敏b,*()   

  1. a 福建工程学院 电子电气与物理学院 福州 350108
    b 中国科学院福建物质结构研究所 中国科学院光电材料化学与物理重点实验室 福州 350002
    c 山东大学 晶体材料研究院 济南 250100
  • 投稿日期:2021-12-09 发布日期:2021-12-30
  • 通讯作者: 罗敏
  • 作者简介:
    庆祝中国科学院青年创新促进会十年华诞.
  • 基金资助:
    国家自然科学基金(21975255); 福建省自然科学基金(2019J01020758); 福建省自然科学基金(2021J011080); 福建省教育厅项目(JT180331); 福建工程学院科研启动基金(GY-Z20042); 中国科学院青年创新促进会(2019303)

Molecular Engineering Design of the First Sr2Be2B2O7-type Fluoride Carbonates AMgLi2(CO3)2F (A=K, Rb) as Deep-Ultraviolet Birefringent Crystal

Yunxia Songa, Fei Liangc, Haotian Tianb, Yan Wua, Min Luob()   

  1. a School of Electronic, Electrical Engineering and Physics, Fujian University of Technology, Fuzhou 350108, China
    b Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure ofMatter, Chinese Academy of Sciences, Fuzhou 350002, China
    c Institute of Crystal Materials, Shandong University, Jinan 250100, China
  • Received:2021-12-09 Published:2021-12-30
  • Contact: Min Luo
  • About author:
    Dedicated to the 10th anniversary of the Youth Innovation Promotion Association, CAS.
  • Supported by:
    National Natural Science Foundation of China(21975255); Natural Science Foundation of Fujian Province(2019J01020758); Natural Science Foundation of Fujian Province(2021J011080); Foundation of Fujian Educational Committee(JT180331); Scientific Research Foundation of Fujian University of Technology(GY-Z20042); Youth Innovation Promotion Association CAS(2019303)

分子结构设计是开发新化合物和通过原子尺度操纵优化晶体结构的一种引人注目的策略. 在这个工作中, 利用分子工程的思想, 基于SBBO结构, 成功设计并合成两个新型氟碳酸盐KMgLi2(CO3)2F和RbMgLi2(CO3)2F. 在两个结构中, a-b平面是由CO3和LiO3F阴离子基团组成的无限[Li3C3O6F3]层, 进一步相邻的层通过F原子连接形成一个独特的[Li6C6O12F3]双层. 这种结构特征对改善晶体的层状生长习性和消除晶体的多晶性有很大的帮助. 光学测试表明, 该系列晶体具有大的双折射和短的紫外截止边, 是深紫外双折射晶体良好的候选材料.

关键词: 结构设计, 深紫外, 氟碳酸盐, 双折射晶体

Molecular engineering design is an effective strategy to develop new compounds and optimize the crystal structure by atomic-scale manipulation. In this work, a novel series of fluoride carbonates AMgLi2(CO3)2F (A=K, Rb) are rationally developed by taking Sr2Be2B2O7 (SBBO) as the parent compound. Their crystal structures are established by single crystal X-ray diffraction. KMgLi2(CO3)2F belongs to centrosymmetric hexagonal system and crystallizes in P63/m with a=b=0.4775 nm, c=1.4782 nm. RbMgLi2(CO3)2F crystallizes in the centrosymmetric trigonal space group P3̅1c with a=b=0.4787 nm, c=1.4966 nm. In all of their structures, the a-b plane is the infinite lattice layer [Li3C3O6F3] made up of [CO3] and [LiO3F] anionic groups. The adjacent layers are further connected with fluorine bridge atoms to form [Li6C6O12F3] double layers. In the structure of KMgLi2(CO3)2F, all the [CO3] groups not only parallel to a-b plane but also align in the exactly same orientation in the same double layers. While the [CO3] groups in RbMgLi2(CO3)2F are parallel to a-b plane but align in the different orientation. But anyway, their structural characteristic is greatly beneficial to improve the layering-growth habit and eliminate polymorphism of a crystal. Since AMgLi2(CO3)2F (A=K, Rb) inherit the beneficial layered structure of SBBO, AMgLi2(CO3)2F (A=K, Rb) should have superior optical properties including short ultraviolet (UV) absorption edges and large birefringences. In order to confirm inference, ultraviolet-visible diffuse reflectance spectroscopy data were recorded at room temperature using a powder sample with BaSO4 as a standard (100% reflectance) on a PerkinElmer Lambda-950 ultraviolet visible-near infrared spectrophotometer over the scan range 200—2500 nm. The results showed KMgLi2(CO3)2F and RbMgLi2(CO3)2F exhibited a wide transparency window, >80%, from 200 to 2500 nm, indicating that both of them had short UV cutoff edges below 200 nm. The birefringent values of the titled compounds were measured on a Nikon ECLIPSE LV100 POL polarizing microscope, which revealed that KMgLi2(CO3)2F and RbMgLi2(CO3)2F had large birefringences (0.111@546.1 nm for KMgLi2(CO3)2F and 0.113@546.1 nm for RbMgLi2(CO3)2F, respectively). In addition, theoretical cal-culations on electronic structure were carried out to explain the experimental results. Our preliminary results indicate that both compounds have promising applications as deep-UV birefringent materials.

Key words: structure design, deep UV, fluoride carbonate, birefringent crystal