Building Nitridic Networks with Phosphorus and Germanium-from Ge^IIP₂N₄ to Ge^IVPN₃

Nitridophosphates and nitridogermanates attract high interest in current research due to their structural versatility. Herein, the elastic properties of GeP₂N₄ were investigated by single-crystal X-ray diffraction (XRD) upon compression to 44.4(1) GPa in a diamond anvil cell. Its isothermal bulk modulus was determined to be 82(6) GPa. At 44.4(1) GPa, laser heating resulted in the formation of multiple crystalline phases, one of which was identified as unprecedented germanium nitridophosphate GePN₃. Its structure was elucidated from single-crystal XRD data (C2/c (no. 15), a = 8.666(5), b = 8.076(4), c = 4.691(2) Å, β = 101.00(7)°) and is built up from layers of GeN₆ octahedra and PN₄ tetrahedra. The GeN₆ octahedra form double zigzag chains, while the PN₄ tetrahedra are found in single zigzag chains. GePN₃ can be recovered to ambient conditions with a unit cell volume increase of about 12%. It combines P^V and Ge^IV in a condensed nitridic network for the first time.