title: Li18P6N16-A Lithium Nitridophosphate with Unprecedented Tricyclic [P6N16]18-Ions.
abstract: Li18P6N16was synthesized by reaction of LiPN2and Li7PN4at 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 PN4tetrahedra forming one vierer- and two additional dreier-rings. To confirm the structure, Rietveld refinement,7Li and31P 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.
authors.affiliation: Department of Chemistry, University of Munich (LMU), Butenandtstr. 5-13, 81377, München, Germany.
authors.forename: Eva-Maria
authors.initials: EM
authors.lastname: Bertschler
authors.affiliation: Institute of Physical Chemistry, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Dietrich
authors.affiliation: Institute of Physical Chemistry, Justus-Liebig-Universität Gießen, Heinrich-Buff-Ring 17, 35392, Gießen, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Janek
authors.affiliation: Department of Chemistry, University of Munich (LMU), Butenandtstr. 5-13, 81377, München, Germany.
authors.forename: Wolfgang
authors.identifier: http://orcid.org/0000-0003-4571-8035
authors.initials: W
authors.lastname: Schnick
keywords: conductivity; high-pressure chemistry; nitrides; phosphates; solid-state structure