In Situ Powder X-ray Diffraction, Synthesis, and Magnetic Properties of the Defect Zircon Structure ScVO4−x

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• 作者：Shahid P. Shafi ; Matthew W. Kotyk ; Lachlan M. D. Cranswick ; Vladimir K. Michaelis ; Scott Kroeker ; Mario Bieringer
• 刊名：Inorganic Chemistry
• 出版年：2009
• 出版时间：November 16, 2009
• 年：2009
• 卷：48
• 期：22
• 页码：10553-10559
• 全文大小：885K
• 年卷期：v.48,no.22(November 16, 2009)
• ISSN：1520-510X

文摘

We report the formation pathway of ScVO₄ zircon from ScVO₃ bixbyite with emphasis on the synthesis and stability of the novel intermediate defect zircon phase ScVO_4−x (0.0 < x ≤ 0.1). The formation pathway has been investigated by means of thermogravimetric/differential thermal analysis and in situ powder X-ray diffraction. The oxidation of ScVO₃ to ScVO₄ involves two intermediates of composition ScVO_3.5+y (0.00 ≤ y ≤ 0.22) and the novel phase ScVO_4−x. ScVO_4−x crystallizes in the defect zircon structure in space group I4₁/amd (141) with a = 6.77761(5) Å and c = 6.14045(8) Å. Oxygen defect concentrations in bulk ScVO_4−x samples range from 0.0 < x ≤ 0.1. ScVO_4−x is compared with the fully oxidized zircon structure ScVO₄ using powder X-ray diffraction, neutron diffraction, and bulk magnetic susceptibility data as well as ⁴⁵Sc and ⁵¹V solid state NMR spectroscopy. ScVO_4−x can only be obtained by oxidation of ScVO₃ or ScVO_3.5+y while the reduction of ScVO₄ does not yield the novel defect structure. Mechanistic insights into the oxidative formation of ScVO₄ via the defect structure are presented.