Phase Equilibria in the System CuO-NiO-P₄O₁₀ and Synthesis, Crystal Structure, and Characterization of the New Copper Nickel Oxide Phosphate Cu₃NiO(PO₄)₂

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• 作者：Iren Weimann ; Jö ; rg Feller and Zdirad Ž&aacute ; k
• 刊名：Zeitschrift für anorganische und allgemeine Chemie
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：643
• 期：4
• 页码：299-305
• 全文大小：2143K
• ISSN：1521-3749

文摘

The system CuO-NiO-P₄O₁₀ was investigated using a solid state reaction between CuO, NiO, and (NH₄)₂HPO₄ in quartz crucibles at 900 °C. The powder samples were characterized by X-ray diffraction, TG/DTA, electrochemical measurements, IR, and UV/Vis spectroscopy. Single crystals of a new quaternary phase Cu₃NiO(PO₄)₂ were achieved by cooling the melted compound in a sealed, evacuated quartz ampoule. Cu₃NiO(PO₄)₂ crystallizes in the monoclinic space group P2₁/n (no 14) with a = 8.2288(2) Å, b = 9.8773(2) Å, c = 8.2777(3) Å, β = 107.82(2)°, Z = 4. The three-dimensional framework consists of distorted tetragonal pyramides [Cu1O₅], distorted planar squares [Cu2O₄], octahedra [Cu3O₆], and [NiO₆] and [PO₄] tetrahedra. The TG-DTA of the new phase showed an incongruent melting at 1055 °C. The open circuit voltage of this material was measured to determine the electrochemical properties. The measurement revealed an initial capacity of 236 Ah·gp>–1p> and a voltage plateau at 2.05 V. Furthermore, it was possible to identify the phase equilibria and to obtain the phase diagram at 900 °C.