Synthesis, structure and magnetic properties of Na₉Co₂O₇, a new mixed-valent sodium cobaltate(II,III)

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• 作者：Sofin ; M. ; Peters ; E.-M. ; Jansen ; M.
• 关键词：Azide/nitrate-route ; Sodium cobalt oxide ; Crystal structure ; Magnetic properties ; Mixed-valent compounds
• 刊名：Solid State Sciences
• 出版年：2004
• 期刊代码：98_12932558
• 类别：ch
• 出版时间：April, 2004
• 卷：6
• 期：4
• 页码：339-344
• 文件大小：227 K

摘要

Na₉Co₂O₇ was prepared via the azide/nitrate route. Stoichiometric mixtures of the precursors (Co₃O₄, NaN₃ and NaNO₃) were heated in a special regime up to 450°C and annealed at this temperature for 100 h in specially designed silver containers. Single crystals have been grown by annealing a Na₂O/Na₉Co₂O₇ mixture (molar ratio 1:2) at 500°C for 2000 h in silver crucibles, which were sealed in glass ampoules under dried Ar. According to the X-ray analysis of the crystal structure (Pca2₁, Z=4, a=9.5477(6) Å, b=9.9040(6) Å, c=10.1919(7) Å, 4103 independent reflections, R₁