Dawson结构多金属含氧酸盐热解性质研究(英文)  

Thermal decomposition behavior of metal-oxygen clusters with Dawson structure

作　　者：孔爱国[1] 李疆[1] 赖克强[1] 张贵荣[1] 丁旵明[1] 单永奎[1] 

机构地区：[1]华东师范大学化学系,上海200062

出　　处：《华东师范大学学报（自然科学版）》2008年第4期78-87,共10页Journal of East China Normal University(Natural Science)

基　　金：国家自然科学基金(20273021)~~

摘　　要：用变温XRD,变温IR以及TG-DTA等方法,系统地研究了具有Dawson结构的Y_m H_n P_2 M_(18)O_(62)·qH_2OOY=K^+,NH_4^+,Cu^(2+);M=Mo,W)的热解性质,获得了它们较为精确的热分解温度,对其热分解的判断方法提出了一些新的见解.结果表明.以钼为配位原子的Dawson结构钾盐,铵盐.铜盐分别在250℃,210℃,240℃发生了热重排,生成了具有Keggin结构的化合物.以钨为配位原子的钾盐在410℃也有相似的行为,但铵盐和铜盐却没有观察到类似的热重排现象,分别在400℃,450℃直接热分解为WO_3.这些结果显示,热重排现象的发生可能与相应的Keggin结构化合物的热稳定性有关.The thermal decomposition behavior of metal-oxygen clusters with Dawson structure, YmHoP2 M18062· qH2O,was systematically investigated using the X-ray power thermodiffractometry and FTIR at different temperatures, TG-DTA. The experimental results indicated that Dawson-type metal-oxygen clusters with anion, l-P2 Mo18O62 ]6 , and different counter cations, NH4 ＋ , Cu2 ＋ , K ＋ , un derwent an irreversible thermal rearrangement around 210 ℃ ,240 ℃ ,250℃, respectively to give the corresponding Keggin-type metal-oxygen clusters containing [PMo12O40]3- as one of the prod- ucts. For the metal-oxygen clusters containing tungsten, the pyrolysis procedure of potassium salt with [P2W18O62]6- anion is similar to that of metal-oxygen clusters with [P2W18O62]6- an- ion, whenas the NH4 ＋ , Cu2 ＋ salts of [P2W18O62]6- seem to decompose directly into WO3 at 400 ℃, 450 ℃, respectively. These results testify that the thermal solid-state rearrangements of Dawson-type anions correlated with the thermal stability of the corresponding Keggin-type com- pounds. Furthermore, some proposals about the criterion and the adjudication of thermal decom- position temperature for metal-oxygen clusters with different thermal decomposition behavior are also given.

关 键 词：DAWSON结构 多金属含氧酸盐 热解 

分 类 号：O461[理学—电子物理学]