新穎三元多硒化物Ba-M’-Se (M’ = Sn, Sb)的合成與特性分析

Abstract

我們利用固態燒結法合成出兩個新穎的三元多硒化物，Ba7Sn2Se14和Ba3Sb2Se7。它們皆是新穎的結構組成，並且含有Se-Se鍵結。產物都經鑑定，且由X光單晶繞射解析結構。並且，我們還進行了物理性質的測量。另外，我們還發現了Eu/Sr-Si-Cu-Se系統中未知物存在的可能。 Ba7Sn2Se14於1,123 K合成。它屬於單斜晶系，空間群為Cm。它的結構由SnSe4四面體，Se22-雙硒和陽離子鋇(II)組成。物理性質測量顯示其具有半導體特性，和理論計算結果相吻合。 Ba3Sb2Se7於1,023 K合成。它屬於斜方晶系，空間群為Cmcm。它的結構由Sb4Se1412-單元組成，而陽離子鋇(II)區隔單元。基本單元Sb4Se1412-由兩個SbSe4蹺蹺板和兩個SbSe5蹺蹺板組成。四個蹺蹺板藉由邊角間隔連接形成一個四邊形。物理性質測量顯示其具有半導體特性，和理論計算結果相吻合。並且，我們還討論了Ba3Sb2Se7+x (x = 0 – 0.5)的可能性。

Two novel ternary polyselenides, Ba7Sn2Se14 and Ba3Sb2Se7 were synthesized by solid-state reaction. They crystallize in new structure types, and both have Se-Se bonds. The products were characterized, and the structures were determined. In addition, we did the measurements of physical properties. Besides, we also discovered a potential of unknown in Eu/Sr-Si-Cu-Se system. Ba7Sn2Se14 was synthesized at 1,123 K. It crystallizes in the monoclinic space group Cm. The structure is constructed of SnSe4 tetrahedra, Se22- diselenides and Ba2+ cations. Measurements of physical properties indicate the semiconducting behavior, and theoretical calculations stand for it. Ba3Sb2Se7 was synthesized at 1,023 K. It crystallizes in the orthorhombic space group Cmcm. The structure is constructed of Sb4Se1412- units, and Ba2+ cations isolate the units. The basic unit Sb4Se1412- is constructed of two SbSe4 seesaws and two SbSe5 seesaws. Four seesaws connect alternately in corner-sharing to form a quadrilateral unit. Measurements of physical properties indicate the semiconducting behavior, and theoretical calculations stand for it. Furthermore, we also discussed the possibility of Ba3Sb2Se7+x (x = 0 – 0.5).