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

5 years ago

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

Robin Niklaus, Wolfgang Schnick, Eva-Maria Bertschler

Li12P3N9 was synthesized by solid-state reaction of Li3N and P3N5 at 790 °C. It is made up of non-condensed [P3N9]12− dreier-rings of PN4-tetrahedra. The corresponding high-pressure polymorph, Li4PN3, was synthesized under high-pressure/high-temperature conditions from Li12P3N9 or LiPN2 and Li7PN4 at 6 or 7 GPa, respectively, using the multianvil technique. Li4PN3 is the first lithium catena-nitridophosphate and contains PN3 zweier-chains of corner sharing PN4-tetrahedra. To confirm the structure elucidated from single-crystal X-ray data, Rietveld refinement, 6Li, 7Li, and 31P solid-state NMR spectroscopy, FTIR spectroscopy and EDX measurements were carried out. To examine the phase transition of Li12P3N9 to Li4PN3 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. Phase transition: Li12P3N9 was synthesized by solid-state reaction at ambient pressure. The first lithium catena-nitridophosphate Li4PN3 was synthesized under high-pressure/high-temperature conditions from Li12P3N9 at 6 GPa. To examine the phase transition of Li12P3N9 to Li4PN3 and to corroborate the latter as the corresponding high-pressure polymorph, DFT calculations and temperature-dependent X-ray powder diffraction were conducted.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201700979