Novel Trigonal ZrWMoO8 Structure and Its Transformations

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• 作者：Xuebin Deng ; Juzhou Tao ; Xiaojing Yang ; Hui Ma ; James W. Richardson Jr. ; Xinhua Zhao
• 刊名：Chemistry of Materials
• 出版年：2008
• 出版时间：March 11, 2008
• 年：2008
• 卷：20
• 期：5
• 页码：1733 - 1740
• 全文大小：823K
• 年卷期：v.20,no.5(March 11, 2008)
• ISSN：1520-5002

文摘

We found two new trigonal polymorphs of cubic ZrWMoO₈ with a negative thermal expansion property and successfully solved and refined their structures using X-ray and/or neutron powder diffraction data. The space group of low temperature trigonal ZrWMoO₈ is R3̄ with cell parameters a = 9.8722(1) Å and c = 17.5455(2) Å, a polytype of the layered trigonal ZrMo₂O₈ structure. The space group of high temperature trigonal ZrWMoO₈ is P3̄ml, and the cell parameters are a = 5.8404(1) Å and c = 6.0671(2) Å. The thermal expansion and phase transition properties of the trigonal and cubic phases were also studied, and consistent structure–property correlation in this system was found. The phase transitions between two forms of trigonal phases and between high temperature trigonal and cubic phases are reversible first order phase transitions. Utilizing the established polymorphous phase transitions, tailorable synthesis of solid oxide materials with controllable thermal expansion property is anticipated in this family.