square antiprisms for X = Cl, and in form of cubes for X = Br. The two structures are not isotypic even though they are made up of analogous building units. The centrosymmetry of the Tl[NbOCl4] structure causes the polar chains to run in opposite directions. The structure of Tl[NbOBr4] is acentric and the polar [NbOBr4−]n chains all point into the same direction. An optical second harmonic generation
铊 (I) 卤化物 TlCl 和 TlBr 分别与
Nb2O5 和 NbCl5 以及 NbBr5 在密闭真空安瓿中在 350 °C 至 300 °C 的温度梯度下进行
化学蒸气传输的条件下反应生成黄色 Tl[NbOCl4]和红色 Tl[NbOBr4],产率为 50%。晶体结构 (Tl[NbOCl4]: 斜方晶系, Pbca, a = 1259.9(1), b = 791.9(1), c = 1506.9(1) pm; Tl[NbOBr4]: 单斜晶系, C2, a = 1304.9(3) , b = 402.7(3), c = 770.6(3) pm, β = 108.150(3)) 由相关的 [NbOX4−]n (X = Cl, Br) 离子和位于链。单个的正方锥体 [NbOX4-] 离子通过不对称的 O···Nb-O 桥连接。Tl+ 离子与卤素原子配位,X = Cl 为强畸变方形反棱柱,X