Pentacoordinate phosphorus in a high-pressure polymorph of phosphorus nitride imide P4N6(NH).

Abstract

Coordination numbers higher than usual are often associated with superior mechanical properties. In this contribution we report on the synthesis of the high-pressure polymorph of highly condensed phosphorus nitride imide P4 N6 (NH) representing a new framework topology. This is the first example of phosphorus in trigonal-bipyramidal coordination being observed in an inorganic network structure. We were able to obtain single crystals and bulk samples of the compound employing the multi-anvil technique. γ-P4 N6 (NH) has been thoroughly characterized using X-ray diffraction, solid-state NMR and FTIR spectroscopy. The synthesis of γ-P4 N6 (NH) gives new insights into the coordination chemistry of phosphorus at high pressures. The synthesis of further high-pressure phases with higher coordination numbers exhibiting intriguing physical properties seems within reach.