Li₁₂P₃N₉ with Non‐Condensed [P₃N₉]¹²⁻‐Rings and its High‐Pressure Polymorph Li₄PN₃ with Infinite Chains of PN₄‐Tetrahedra

Abstract

Li P N was synthesized by solid-state reaction of Li N and P N at 790 °C. It is made up of non-condensed [P N ] dreier-rings of PN -tetrahedra. The corresponding high-pressure polymorph, Li PN , was synthesized under high-pressure/high-temperature conditions from Li P N or LiPN and Li PN at 6 or 7 GPa, respectively, using the multianvil technique. Li PN is the first lithium catena-nitridophosphate and contains PN zweier-chains of corner sharing PN -tetrahedra. To confirm the structure elucidated from single-crystal X-ray data, Rietveld refinement, Li, Li, and P solid-state NMR spectroscopy, FTIR spectroscopy and EDX measurements were carried out. To examine the phase transition of Li P N to Li PN at 6 GPa and to corroborate the latter as the corresponding high-pressure polymorph, DFT calculations were conducted. Electronic band gap and electron localization function (ELF) calculations were carried out to elucidate the electronic properties and bonding behavior of both polymorphs.

Reversible Polymerization of Adamantane‐type [P4N10]10− Anions to Honeycomb‐type [P2N5]5− Layers under High‐Pressure

“…Similar with other nitridophosphates, the bond lengths to terminal nitrogen atoms of PN 4 tetrahedra are shorter than those to bridging ones . These P−N distances are in accordance with values found in other lithium nitridophosphates . The P/N layers are surrounded by Li + ions, which are coordinated by N with coordination numbers 4, 5, and 6.…”

“…(e) Zweier ‐chains in Li 4 PN 3 . (f) A three‐dimensional network structure in LiPN 2 . (P: black, N: green).…”

“…Li 7 PN 4 has the lowest atomic ratio P/N (Figure a) . In Li 12 P 3 N 9 [P 3 N 9 ] 12− units form dreier ‐rings of PN 4 tetrahedra (Figure b) . Li 18 P 6 N 16 is composed of one vierer ‐ring with two annelated dreier ‐rings (Figure c) .…”

“…Li 4 PN 3 is the high‐pressure polymorph of Li 12 P 3 N 9 (6 GPa and 820 °C) and represents the first chain like structure in lithium nitridophosphates. It transforms back to Li 12 P 3 N 9 at 650 °C (Figure e) . LiPN 2 is made up of a three‐dimensional network structure with corner sharing PN 4 tetrahedra isoelectronic to SiO 2 (Figure f) …”

SrH4P6N12 and SrP8N14: Insights into the Condensation Mechanism of Nitridophosphates under High Pressure

“…As examples, the parentc ompounds, P 3 N 5 ,H PN 2 (i.e.,P N(NH))a nd HP 4 N 7 (i.e.,P 4 N 6 (NH)) can be named, showingr are structural motifs like triply bridging N [3] atoms or edge-sharing tetrahedra. [15][16][17][18] Another synthesis route is based on thermal dissociation of metal azides. [5,10] Furthermore, calculations predicted the existence of afurtherhigh-pressure polymorph, d'-P 3 N 5 ,exhibiting trigonal bipyramids as fivefold coordination spheres of P, as well as sixfold coordinated Pi na no ctahedral environment.…”