Herein, we report on the synthesis, isolation, and comprehensive characterization (m.p., ATR-IR/Raman, elemental analysis, 14 N NMR) of tetraazidozincate anions [Zn(N 3 ) 4 ] 2in a series of [Ph 4 P] + and [PNP] + [PNP = bis(triphenylphosphine)iminium] salts. The phase polymorphism in [Ph 4 P] 2 -[Zn(N 3 ) 4 ] was investigated by temperature-dependent Raman spectroscopy and by powder and single-crystal X-ray diffraction experiments, which indicate the occurrence of five roomtemperature-stable, and one common high-temperature phase, [a]