SrP₃N₅NH. A framework-type imidonitridophosphate featuring structure-directing hydrogen bonds

Nitridophosphates and imidonitridophosphates show intriguing structural diversity, including unprecedented structure types. Highly condensed strontium imidonitridophosphate SrP₃N₅NH has been synthesized at 8 GPa and 1100 C using a high-pressure high-temperature approach starting from stoichiometric amounts of Sr(N₃)₂, P₃N₅ and NH₄Cl. Herein, NH₄Cl was used as a hydrogen source and as a precursor for in situ formation of SrCl₂, which acts as mineralizer and facilitates growth of single-crystals with a diameter of ≤30 μm. SrP₃N₅NH (P2₁/c (no. 14), a=5.01774(2), b=8.16912(4), c=12.70193(5) Aa, β=101.7848(3) , Z=4) adopts an unprecedented network structure, represented by the point symbol (3.4.5.6.7²)(3.4.5.7².8)(3.6.7³.8). This unique three nodal P/N(H) network is stabilized by moderately strong hydrogen bonds causing a structure-directing effect, which has not yet been reported for imidonitridophosphates. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)