Synthesis and Characterization of a New Pentaborate, KNa2CdB5O10  

作　　者：陈学安 张亚华 常新安 肖卫强 

机构地区：[1]College of Materials Science and Engineering,Beijing University of Technology [2]Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology

出　　处：《Chinese Journal of Structural Chemistry》2018年第5期719-729,共11页结构化学（英文）

基　　金：Supported by the National Natural Science Foundation of China(No.20871012)

摘　　要：A new pentaborate, KNa2CdB5O（10）, has been synthesized and its crystal structure was determined by single-crystal XRD method with the following crystal data： KNa2CdB5O（10）, Pccn, a = 18.4555（13）, b = 8.3040（10）, c = 12.8772（9） A, V = 1973.5（3） A3, Z = 8, Mr = 411.53, Dc= 2.770 g/cm3, μ = 2.765 mm（-1）, F（000） = 1552, R = 0.0648 and w R = 0.1756 for 1684 observed reflections and 175 variables. It contains the double ring [B5O（10）]（5-） groups composed of one BO4 tetrahedron and four BO3 triangles that are bridged by tetrahedral Cd（2＋） centers via common O atoms to form 2D [CdB5O（10）]n（3n-） layers, with A＋（A = K/Na, Na） cations situated between and within the layers. IR spectrum confirms the existence of BO3 and BO4 groups. UV-VIS diffuse reflectance spectrum shows a band gap of about 3.44 eV and solid-state fluorescence spectrum exhibits a broad emission band at around 386 nm. Band structure calculations indicate that KNa2CdB5O（10） is an indirect band-gap insulator, with the calculated energy gap（3.68 eV） close to the experimental one.A new pentaborate, KNa2CdB5O（10）, has been synthesized and its crystal structure was determined by single-crystal XRD method with the following crystal data： KNa2CdB5O（10）, Pccn, a = 18.4555（13）, b = 8.3040（10）, c = 12.8772（9） A, V = 1973.5（3） A3, Z = 8, Mr = 411.53, Dc= 2.770 g/cm3, μ = 2.765 mm（-1）, F（000） = 1552, R = 0.0648 and w R = 0.1756 for 1684 observed reflections and 175 variables. It contains the double ring [B5O（10）]（5-） groups composed of one BO4 tetrahedron and four BO3 triangles that are bridged by tetrahedral Cd（2＋） centers via common O atoms to form 2D [CdB5O（10）]n（3n-） layers, with A＋（A = K/Na, Na） cations situated between and within the layers. IR spectrum confirms the existence of BO3 and BO4 groups. UV-VIS diffuse reflectance spectrum shows a band gap of about 3.44 eV and solid-state fluorescence spectrum exhibits a broad emission band at around 386 nm. Band structure calculations indicate that KNa2CdB5O（10） is an indirect band-gap insulator, with the calculated energy gap（3.68 eV） close to the experimental one.

关 键 词：KNa2CdB5O（10） BORATE SYNTHESIS X-ray diffraction crystal structure 

分 类 号：O613.81[理学—无机化学]