Li<sub>18sub>P<sub>6sub>N<sub>16sub>—A Lithium Nitridophosphate with Unprecedented Tricyclic [P<sub>6sub>N<sub>16sub>]<sup>18−sup> Ions
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- 作者：Eva-Maria Bertschler ; Christian Dietrich ; Prof. Dr. Jü ; rgen Janek and Prof. Dr. Wolfgang Schnick
- 刊名：Chemistry - A European Journal
- 出版年：2017
- 出版时间：February 10, 2017
- 年：2017
- 卷：23
- 期：9
- 页码：2185-2191
- 全文大小：994K
- ISSN：1521-3765
文摘
Li<sub>18sub>P<sub>6sub>N<sub>16sub> was synthesized by reaction of LiPN<sub>2sub> and Li<sub>7sub>PN<sub>4sub> at 5.5 GPa and 1273 K employing the multi-anvil technique. It is the first lithium nitridophosphate obtained by high-pressure synthesis. Moreover, it is the first example received by reaction of two ternary lithium nitrides. The combination of high-pressure conditions with a Li<sub>3sub>N flux enabled a complete structure determination using single-crystal X-ray diffraction. The hitherto unknown tricyclic [P<sub>6sub>N<sub>16sub>]<sup>18−sup> anion is composed of six vertex-sharing PN<sub>4sub> tetrahedra forming one vierer- and two additional dreier-rings. To confirm the structure, Rietveld refinement, <sup>7sup>Li and <sup>31sup>P solid-state NMR spectroscopy, FTIR spectroscopy and EDX measurements were carried out. To validate the ionic properties, the migration pathways of the Li<sup>+sup> ions were evaluated, and the conductivity and its temperature dependence were determined by impedance spectroscopy measurements. In order to obtain a clearer picture of the formation mechanism of this compound class, different synthetic approaches were compared, enabling targeted syntheses of unprecedented P/N-anion topologies with intriguing properties.