Crystal structure and negative thermal expansion of solid solution Lu_2W_(3-x)Mo_xO_(12)  

作　　者：Jie Peng Xin-zhi Liu Fu-li Guo Song-bai Han Yun-tao Liu Dong-feng Chen Zhong-bo Hu 

机构地区：[1]Experimental Physics Center, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China [2]College of Chemistry and Chemical Engineering, Graduate University of Chinese Academy of Sciences, Beijing 100049, China [3]China Institute of Atomic Energy, Beijing 102413, China [4]College of Chemistry, Beijing Normal University, Beijing 100875, China

出　　处：《International Journal of Minerals,Metallurgy and Materials》2010年第6期786-790,共5页矿物冶金与材料学报（英文版）

基　　金：supported by the China Postdoctoral Science Foundation (No.20080430556);the Major State Basic Research and Development Program of China (No.2006CB705600)

摘　　要：A new series of solid solutions Lu2W3-xMoxO12 （0.5≤r≤2.5） were successfully synthesized by the solid-state method. Their crystal structure and negative thermal expansion properties were studied using high-temperature X-ray powder diffraction and the Rietveld method. All samples of rare-earth ttmgstates and molybdates are found to crystallize in the same orthorhombic structure with space group Pnca and show the negative thermal expansion phenomena related to transverse vibration of bridging oxygen atoms in the structure. Thermal expansion coefficients （TEC） of Lu2W3_xMoxO12 are determined as -20.0× 10^-6 K^-1 for x=0.5 and -16.1×10^-6 K^-1 for x=2.5 but -18.6× 10^-6 and -16.9× 10^-6K^-1 for unsubstituted Lu2W3012 and Lu2M03012 in the identical temperature range of 200 to 800℃. High-temperature X-ray diffraction （XRD） data and bond length analysis suggest that the difference between W-O and Mo-O bond is responsible for the change of TECs after the element substitution in this series of solid solutions.A new series of solid solutions Lu2W3-xMoxO12 （0.5≤r≤2.5） were successfully synthesized by the solid-state method. Their crystal structure and negative thermal expansion properties were studied using high-temperature X-ray powder diffraction and the Rietveld method. All samples of rare-earth ttmgstates and molybdates are found to crystallize in the same orthorhombic structure with space group Pnca and show the negative thermal expansion phenomena related to transverse vibration of bridging oxygen atoms in the structure. Thermal expansion coefficients （TEC） of Lu2W3_xMoxO12 are determined as -20.0× 10^-6 K^-1 for x=0.5 and -16.1×10^-6 K^-1 for x=2.5 but -18.6× 10^-6 and -16.9× 10^-6K^-1 for unsubstituted Lu2W3012 and Lu2M03012 in the identical temperature range of 200 to 800℃. High-temperature X-ray diffraction （XRD） data and bond length analysis suggest that the difference between W-O and Mo-O bond is responsible for the change of TECs after the element substitution in this series of solid solutions.

关 键 词：rare earth compounds MOLYBDATES rare-earth tungstates negative thermal expansion X-ray diffraction 

分 类 号：O614.121[理学—无机化学] TB34[理学—化学]