熔鹽法合成之鈦矽酸鹽及其晶體結構研究;Flux Synthesis of Titanium Silicates

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題名:	熔鹽法合成之鈦矽酸鹽及其晶體結構研究;Flux Synthesis of Titanium Silicates
作者:	陳威宇;Chen, Wei-Yu
貢獻者:	化學學系
關鍵詞:	晶體結構;鈦矽酸鹽;熔鹽法
日期:	2017-07-20
上傳時間:	2017-10-27 12:57:19 (UTC+8)
出版者:	國立中央大學
摘要:	本論文以熔鹽法合成三個新穎的鈦矽酸鹽化合物[Li3Cs4F](TiO)(Si4O12) (A1)、Cs3(TiOF)Si4O10 (A2) 以及Na4(Ti2OF)Si8O20 (A3)。利用單晶X光繞射方法鑑定出此三種化合物的晶體結構，再以X光能量散布光譜儀分析確定元素組成、並針對A3化合物，試圖以高溫固態反應合成法合成純相，以供後續性質研究。化合物A1為四價的鈦矽酸鹽，結構中矽酸鹽以[Si4O13]10-的形式和TiO5以共用氧原子的方式相連形成在b軸延伸的一維鏈狀結構，Cs+ 、Li+、F-離子則座落在鏈與鏈之間，氟離子與周圍的三個鋰離子及三個銫離子配位，形成一個扭曲的多面體。由於鈦矽酸鹽容易形成三維或二維結構，此化合物為在系列中相當少見的一維結構。化合物A2為四價的鈦矽酸鹽，在ac平面具有由矽氧四面體以共角形成的[Si2O5]n2n-層狀結構，再與TiO6及TiO4F2八面體以共用氧原子的方式連接，形成三維骨架，結構中具有沿著a軸延伸的九圓環通道，銫離子座落在通道中，並沿著a軸方向排列。化合物A3為三四混價的鈦矽酸鹽，結構中具有由Ti2O9F做重覆單元，以共用氧或氟形成的鏈，因此有O-Ti-F-Ti-O這種鍵結，以短-長-長-短形式分佈於此鏈狀結構。上述的鏈狀結構沿著c軸延伸，而矽酸鹽結構 [Si4O12]8- 以共用氧原子的方式與這些鏈連接， Na+離子分布在結構的孔隙中。 ;Three new alkali metal titanium silicates, [Li3Cs4F][(TiO)(Si4O12)] (A1),Cs3[(TiOF)(Si4O10)] (A2) and Na4[(Ti2OF)Si8O20] (A3), were synthesized by the flux method, and structurally characterized by powder and single X-ray diffraction. These compounds were further characterized by EDS or XPS. Pure polycrystalline product of A3 was synthesized by the high temperature solid-state reaction for SQUID measurements. Compound A1 is a lithium and cesium-containing titanium silicate. The crystal structure consists of 1-D chains which consists of [Si4O13]10- which share the oxygen corners of TiO5 square pyramids to form slabs along the b axis. The Li+、Cs+ cations and F- anions are located at sites in the interchain regions. Each F- anion are coordinated by three Li+ and three Cs+ cations, forming a distorted polyhedral. This compound is a 1-D chain structure which is rare in titanium silicates. Compound A2 is a titanium(VI) silicate. The structure consists of [Si2O5]n2n- layers in the ac plane which are connected by sharing corners between SiO4 tetrahedral units and these layers are connected by TiO6 and TiO4F2 octahedral via sharing oxygen atoms to form 3D framework. There are nine-ring channels along the a axis where the Cs+ cations are located. Compound A3 is a mixed-valence Ti(III,IV) silicate. Its crystal structure consists of infinite chains along the c axis, which are formed of TiO5F octahedral sharing trans corner. The Ti-(O, F)-Ti-(O, F) bonds are alternatively short and long along the chain. The chains are connected by silicate chains with formula [Si4O12]8- by corner-sharing to form a 3-D framework. The Na+ cations are located at sites in the structural channels.
顯示於類別:	[化學研究所] 博碩士論文

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