混合价多硒代锗酸盐K_2Ge_4Se_8的固相合成、晶体结构和反射光谱研究

Solid State Synthesis, Crystal Structure and Reflectance Spectra of K_2Ge_4Se_8

采用反应性熔盐法以n(K2 Se3 )∶n(Ge)∶n(Se) =2∶1∶6的摩尔比 ,在 773K下反应 5d ,得到一种新的混合价硒代锗酸盐 ,K2 Ge4Se8.该晶体属于单斜系 ,空间群为P2 1 /c ,晶胞参数a =0 73 75 2 ( 5 )nm ,b =1 2 2 3 9( 2 )nm ,c =1 7468( 4 )nm ,β =96 0 2 ( 3 )° ,V =1.5 680 ( 5 )nm3 ,Z =4.偏差因子R1 =0 0 64 3 ,wR2 =0 15 47.K2 Ge4Se8晶体具有层状结构 ,二维的2∞[Ge4Se8] 2 -层负离子和K+ 正离子堆积而成 ,层与层按ABAB排列 .K2 Ge4Se8属于Zintl型化合物 ,属于半导体 ,反射光谱法测定的光学能隙 (Eg)为 1 8eV .

A novel ternary metal selenide, K 2Ge 4Se 8, bipotassium octaseleno tetragermanate was synthesized employing the molten salt reaction in a molar ratio of n (K 2Se 3)∶ n (Ge)∶ n (Se)=2∶1∶6 at 773 K for 5 d. The crystal crystallized in the monoclinic space group P 2 1/ c with the unit cell parameters a =0 73752(5) nm, b =1 2239(2) nm, c =1 7468(4) nm, β =96 02(3)°, V =1 5680(5) nm 3, and Z =4. K 2Ge 4Se 8 has a layered crystal structure containing two dimentional networks, 2 ∞[Ge 4Se 8] 2- anions separated by K + cations. The layers are packed in a sequence, ABAB, in the crystal. A reflectance spectroscopy study revealed the nature of semiconductor with an energy gap of 1 8 eV for the title compound.