Li18P6N16-A Lithium Nitridophosphate with Unprecedented Tricyclic [P6N16](18-) Ions

Bertschler, Eva-Maria; Dietrich, Christian; Janek, Jürgen and Schnick, Wolfgang (2017): Li18P6N16-A Lithium Nitridophosphate with Unprecedented Tricyclic [P6N16](18-) Ions. In: Chemistry-A European Journal, Vol. 23, No. 9: pp. 2185-2191

Abstract

Li18P6N16 was synthesized by reaction of LiPN2 and Li7PN4 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 Li3N flux enabled a complete structure determination using single-crystal X-ray diffraction. The hitherto unknown tricyclic [P6N16](18-) anion is composed of six vertex-sharing PN4 tetrahedra forming one vierer- and two additional dreier-rings. To confirm the structure, Rietveld refinement, Li-7 and P-31 solid-state NMR spectroscopy, FTIR spectroscopy and EDX measurements were carried out. To validate the ionic properties, the migration pathways of the Li+ 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.

• Item Type: Journal article
• Faculties: Chemistry and Pharmacy > Department of Chemistry
• Subjects: 500 Science > 540 Chemistry
• ISSN: 0947-6539
• Language: English