Diverse Hf-Q Chains Existing in the Ternary Eu-Hf-Q(Q = S,Se) System

Two ternary Eu-Hf-Q(Q = S, Se) chalcogenides, EuHfSe3(1) and Eu5 Hf3 S12(2), have been synthesized by a facile solid state routine and structurally characterized by single-crystal X-ray diffraction technique. They crystallize in the orthorhombic space group Pnma(1) or hexagonal P 6 2 m(2), and diverse Hf-Q chains exist in their 3 D structures. The electronic structure of 1 is also calculated according to density functional theory.     

硫属卤化物红外二阶非线性光学晶体材料的研究进展

对二阶红外非线性光学晶体材料的研究是当前激光及非线性光学领域研究的重点、难点和热点之一.由于满足应用需求的材料比较缺乏,很有必要从源头上探索潜在的新型红外非线性光学晶体材料.硫属化合物和卤化物是红外非线性光学晶体新材料探索的主要体系,前者一般表现出大的倍频效应和宽的红外窗口,后者则多具有大的光学带隙,即高的抗激光损伤阈值.结合两者的优势,有望获得综合非线性光学性能优异的新材料.在此背景下,本文综述了近期硫属卤化物红外非线性光学晶体材料的研究现状,包括含S8单元的卤化物、包盐硫属卤化物和钡基硫属卤化物.这些硫属卤化物的粉末样品大都表现出优异的非线性光学性能.最后,本文讨论了该方向未来研究的机会和重点.     

Two Ternary Europium Chalcogenides Eu_(1-x)Ga_2Te_4(x≈0.19) and EuY_2Se_4, Experimental and Theoretical Investigations

Two ternary europium chalcogenides, Eu_(1-x)Ga_2Te_4(x ≈ 0.19)(1) and EuY_2Se_4(2), have been synthesized by a facile solid-state route using boron as the reducing reagent. Eu_(1-x)Ga_2Te_4 crystallizes in the tetragonal space group I4/mcm with a = 8.2880(9), c = 6.7439(12) ?, V = 463.24(13) ?~3, and Z = 2. EuY_2Se_4 crystallizes in the orthorhombic space group Pnma with a = 12.4726(16), b = 4.1204(6), c = 14.849(2) ?, V = 763.11(19) ?~3, and Z = 4. Eu_(1-x)Ga_2Te_4 belongs to the Tl Se-type 3D closed structure, while EuY_2Se_4 adopts the CaFe_2O_4-type 3D channel structure. The optical band gap of Eu_(1-x)Ga_2Te_4 is determined to be 0.48 eV. Electronic structures of 1 and 2 are calculated using TB-LMTO software.     

Syntheses and Single-crystal Structures of Er3GexGeS7 （1/4≤x≤ 1/2）

As part of our systematic research on the acentric rare earth chalcogenides, the ErAlGeS5/KBr, Er3AgGeS7/KBr and Er6Ge3S14/KBr systems were investigated and three compounds belonging to the R6B2C2Q14 （R = rare earth, B = 6-coordinated element, C = 4-coordinated element, Q = S and Se） family were identified. These compounds crystallize in the P63 space group, and the crystal data are as follows： Er3Ge1/4GeS7, a = 9.6480（14）, c = 5.7920（12） A^°, Z = 2; Er3Ge0.382（8）GeS7, a = 9.6360（14）, c = 5.8460（12） A^°, Z = 2; Er3Ge1/2GeS7, a = 9.6061（13）, c = 5.8346（18）A^°, Z = 2. Single-crystal analysis indicated that the Er3GexGeS7 （x = 1/4, 0.382（8）, 1/2） structures consist of three types of building blocks： ErS7, GeS4 and GeS6 units. Er3MxGeS7 are deficient compounds with the B sites occupied partly by Ge（Ⅳ） and/or Ge（Ⅱ）.     

五个无心四元硫化物AlxLn3（SiyAl1-y）S7（Ln=Y,Gd,Dy）和In0.33Sm3SiS7的合成、结构及性质

使用一种新的高温固相反应方法合成得到了五个新的异质同构的四元稀土硫化物.它们结晶于六方晶系的手性空间群P63,属于ALn3EQ7（A：碱金属或货币金属 Ln：稀土元素 E：第IVA族元素 E：硫属元素）结构类型,晶胞参数为a=9.621（1）～10.038（2）A,c=5.672（2）～5.939（1）A,V=476.1（1）～494.9（2）A^3,Z=2.它们的晶体结构可以描述为：LnS8双帽三棱柱之间相互连接成三维框架结构,而A位和E位原子分别占据所形成的八面体和四面体空隙.化合物4的光学和磁性质的研究表明：它是光学带隙为2.34eV的半导体,并表现出类似于反铁磁相互作用的磁行为.