共沉淀法制备ZrW_2O_8及其中间产物的晶体结构

Crystal Structure of ZrW_2O_8 and the Intermediate Products Prepared with Coprecipitation Method

以仲钨酸铵[(NH4)10W12O41.5H2O]和氧氯化锆(ZrOCl2.8H2O)为原料,采取共沉淀法制备具有负热膨胀系数的钨酸锆(ZrW2O8)。采用X射线衍射仪(XRD)分析合成过程的前驱体、中间体和最终产物等的晶体结构,并采用FullProf-Suite程序和Material Studio程序分别对ZrW2O8晶体的XRD数据进行处理,精化修正其原子坐标参数和晶体结构参数。结果表明,前驱体结构呈无定形态;中间体的结晶度为33.66%;最终产物为立方晶系的ZrW2O8,空间群为P213(198),晶胞参数a0为0.915 98 nm,晶胞体积为0.768 52 nm3,衍射峰指标化的可靠性因子F(30)=57.1(44),峰形因子RP为0.251 9,权重因子Rwp为0.134 3。

Negative thermal expansion zirconium tungstate ZrW2O8 powder was prepared from ammonium metatungstate （NH4）10W12O41·5H2O and zirconium oxychloride ZrOCl2 · 8H2O with coprecipitation method. The physical structure of the precursor, intermediate powder in the synthesis and final product powder were analyzed by X-ray diffraction, and XRD data of ZrW2O8 crystal structure were treated by FullProf-Suite software and Material Studio software, in which the atomic coordinate parameter and the crystal structure parameter of ZrW2O8 were refined. The results indicated that the structure of precursor was identified as amorphous, the crystallinity of the intermediate was 33. 66%, and the final product was cubic phase ZrW2O8 with space group of P213 （198）, cell parameter of 0. 915 98 nm and cell volume of 0. 768 52 nm^3. Through XRD data treatment it was obtained that the figure of merit for the index F（30） was 57. 1 （44）, the peak profile simulation factor RP was 0. 251 9 and the weight factor Rwp was 0. 134 3.