Na_3La_2(BO_3)_3的晶体结构(英文)

Crystal Structure of Sodium Lanthanum Borate Na_3La_2(BO_3)_3

以Na2 CO3 H3 BO3 NaF为助熔剂 ,使用顶部籽晶法生长出Na3 La2 (BO3 ) 3 透明单晶。测定了Na3 La2 (BO3 ) 3 的晶体结构 ,该晶体属正交晶系 ,空间群 :Amm2 (No .38) ,晶胞参数为a =0 .5 15 80 (10 )nm ,b =1.135 0 (2 )nm ,c =0 .732 30(15 )nm ,α=β=γ =90° ,V =0 .4 2 871(15 )nm3 ,密度 :4 .0 5 3g/cm3 。晶体结构中的硼氧基团是平面的BO3 基团 ,BO3 基团相互独立 ,且与Na(1)O6、Na(2 )O8、Na(3)O6和La(1)O9配位多面体连结形成三维网络骨架结构。讨论了Na3 La2(BO3 ) 3 的晶体结构与倍频效应的关系。

Single crystal of Na_3La_2(BO_3)_3 was grown from the high temperature solution by employing Na_2CO_3-H_3BO_3-NaF as fluxes. The structure was established by single-crystal X-ray diffraction method. The compound crystallizes in the orthorhombic system, space group Amm2 (No.38) with a=0.51580(10) nm, b=1.1350(2) nm, c=0.73230(15) nm, α=β=γ=90°, V=0.42871(15) nm, and Z=2. Its three-dimensional network structure is formed by isolated BO_3 triangles held together by the Na(1)O_6, Na(2)O_8, Na(3)O_6, and La(1)O_9 polyhedra. The relationship between the structure and optical second harmonic generation (SHG) effect of Na_3La_2(BO_3)_3 crystal was also discussed.