Structure, Phase Transition, and Controllable Thermal Expansion Behaviors of Sc2-xFexMo3O12

Published

September 2, 2014

Author(s)

Meimei Wu, Xinzhi Liu, Dongfeng Chen, Qingzhen Huang, Hui Wu, Yuntao Liu

Abstract

The crystal structures, phase transition and thermal expansion behaviors of solid solutions Sc_2-xFe_xMo₃O₁₂(0less than or equal to}xless than or equal to}2) have been examined using X-ray diffraction (XRD), neutron powder diffraction (NPD) and differential scanning calorimetry (DSC). At room temperature, samples crystallize in a single orthorhombic structure for the compositions of x < 0.6 and monoclinic for x ≥ 0.6, respectively. DSC results indicate that the phase transition temperature from monoclinic to orthorhombic structure is enhanced by increasing the Fe³⁺ content. High temperature XRD and NPD results show that Sc_1.3Fe_0.7Mo₃O₁₂ exhibits near zero thermal expansion, and the volumetric coefficient of thermal expansion derived from XRD and NPD are 0.28x10^-6 °C^-1 (250-800 °C) and 0.65x10^-6 °C^-1 (227-427 °C), respectively. NPD results of Sc₂Mo₃O₁₂ (x=0) and Sc_1.3Fe_0.7Mo₃O₁₂ (x=0.7) indicate that Fe substitution for Sc induces reduction of the mean Sc(fe)-Mo non-bond distance and the different thermal variations of Sc(Fe)-O5-Mo2 and Sc(Fe)-O3-Mo₂ bond angles. The correlation between the displacements of oxygen atoms and the variation of unit cell parameters was investigated in details for Sc₂Mo₃O₁₂O₁₂ and Sc_1.3Fe_0.7Mo₃O₁₂.

Citation

Inorganic Chemistry

Volume

53

Pub Type

Journals

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Keywords

X-ray diffraction, Neutron powder diffraction, Thermal expansion, Molybdates

Citation

Wu, M. , Liu, X. , Chen, D. , Huang, Q. , Wu, H. and Liu, Y. (2014), Structure, Phase Transition, and Controllable Thermal Expansion Behaviors of Sc_2-xFe_xMo₃O₁₂, Inorganic Chemistry, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=917074 (Accessed May 2, 2024)