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Stishovite's Relative: A Post‐Coesite Form of Phosphorus Oxonitride
Author(s) -
Vogel Sebastian,
Baumann Dominik,
Niklaus Robin,
Bykova Elena,
Bykov Maxim,
Dubrovinskaia Natalia,
Dubrovinsky Leonid,
Schnick Wolfgang
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201803610
Subject(s) - stishovite , coesite , orthorhombic crystal system , crystallography , diffraction , x ray crystallography , synchrotron , chemistry , crystal structure , materials science , bulk modulus , diamond anvil cell , eclogite , optics , biology , subduction , composite material , tectonics , paleontology , quartz , physics
Phosphorus oxonitride (PON) is isoelectronic with SiO 2 and may exhibit a similar broad spectrum of intriguing properties as silica. However, PON has only been sparsely investigated under high‐pressure conditions and there has been no evidence on a PON polymorph with a coordination number of P greater than 4. Herein, we report a post‐coesite (pc) PON polymorph exhibiting a stishovite‐related structure with P in a (5+1) coordination. The pc‐PON was synthesized using the multianvil technique and characterized by powder X‐ray diffraction, solid‐state NMR spectroscopy, TEM measurements and in situ synchrotron X‐ray diffraction in diamond anvil cells. The structure model was verified by single‐crystal X‐ray diffraction at 1.8 GPa and the isothermal bulk modulus of pc‐PON was determined to K 0 =163(2) GPa. Moreover, an orthorhombic PON polymorph ( o ‐PON) was observed under high‐pressure conditions and corroborated as the stable modification at pressures above 17 GPa by DFT calculations.