Un nouveau tetraedre azote NaN4: Preparation et structure de NaGe2N3

The NaGe₂N₃ nitride is prepared from the NaGeON oxynitride. It presents a normal tetrahedral structure related to the wurtzite type. The unit cell is orthorhombic with a = 9.8662(15), b = 5.7830(9), and c = 5.1221(5) Å, space group Cmc2₁ (No. 36). The structure refinement has been made using multicomponent profile analysis of time-of-flight neutron diffraction data. The germanium and sodium atoms are ordered among one-half of the tetrahedral sites built up by the slightly distorted hexagonal close-packing of the nitrogen atoms. It is the first example of a stable entirely nitrided environment for the sodium atom.