摘要
利用熔盐籽晶法在组分配比为20mol%Li_2O:80mo1%B_2O_3的熔体中培养出 Li_2O·3B_2O_3大单晶,晶体呈板状,X 射线单晶结构分析证实所获得的单晶为 Li_2O·3B_2O_3的晶体,其结构属正交晶系,空间群为 P2_1cn,晶胞参数α=5.141(6)(?),b=7.378(4)(?),c=8.446(3)(?),U=320.3(?)~3,每个单胞含4个 LiB_3O_5分子,理论密度2.48g/cm^3,实测密度2.47g/cm^3。Li_2O·3B_2O3晶体具有 ADP 量级的倍频效应,其主要原因在于阴离子基团的基本单位是[B_3O_7]构型,这种构型有利于产生较大的倍频效应。另外,根据本文的研究结果我们认为:高温相Li_2O·4B_2O_3并不以稳定相存在,它很可能是Li_2O·3B_2O_3和B_2O_3的混合物。
The growth and structure of the crystal of Li_2O·3B_2O_3,a newnonlinear optical material developed in our laboratory by flux seeding method,are reported in this paper.X-ray analysis shows that the crystal belongs to theorthorhombic system with space group P2_1cn,and that its unit cell dimensionsare a=5.141(6)(?),b=7.378(4)(?)and c=8.446(3)(?).Each cell contains 4 LiB_3O_5molecules.The calculated and measured densities are 2.48g/cm^3 and 2.47g/cm^3 res-pectively.Since the basic structural units are B_3O_7 groups which are favorablefor proaucing a large SHG effect,the SHG coefficient of LiO·3B_2O_3 crystals is comparable to that of ADP.It has been reported by some investigators thatthe compound Li_2O·4B_2O_3 exists in two crystalline forms.However,the X-raypowder diffraction data obtained in the present investigation shows that the hightemperature form Li_2O·4B_2O_3 is probally a mixture of Li_2O·3B_2O_3 and B_2O_3.
出处
《人工晶体学报》
EI
CAS
CSCD
1990年第1期33-38,共6页
Journal of Synthetic Crystals
关键词
硼酸盐
晶体
单晶
熔盐籽晶法
锂
borate crystal
nonlinear optical crystal
flux seeding method
x-ray diffraction
crystal structure
