Building Nitridic Networks with Phosphorus and Germanium-from Ge II P 2 N 4 to Ge IV PN 3 .

Nitridophosphates and nitridogermanates attract high interest in current research due to their structural versatility. Herein, the elastic properties of GeP 2 N 4 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 GePN 3 . Its structure was elucidated from single-crystal XRD data ( C 2/ 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 GeN 6 octahedra and PN 4 tetrahedra. The GeN 6 octahedra form double zigzag chains, while the PN 4 tetrahedra are found in single zigzag chains. GePN 3 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.