Synthesis and crystal structure of Sr2ZnN2 and Ba2ZnN2

Ternary nitrides, Sr2ZnN2 and Ba2ZnN2, were prepared from Sr or Ba along with Zn metal using Na metal and NaN3 as a flux and nitrogen source, respectively. The single crystals were obtained by slow cooling from 750°C. Since these compounds hydrolyze in moist air, the crystals were isolated by washing away excess Na with liquid NH3 in an inert environment. The structures were determined by single crystal X-ray diffraction: tetragonal, space group I 4/mmm with Z = 2, a = 3.8568(2), c = 12.935(1) Å, and R 1 = 0.049 for Sr2ZnN2, and a = 4.152(1), c = 13.055(3) Å, and R 1 = 0.039 for Ba2ZnN2. Sr2ZnN2 and Ba2ZnN2 are isostructural with Ca2ZnN2 (Na2HgO2 type) and contain linear [NZnN]4− nitridometallate anions.