Ammonothermal Synthesis and Characterization of Li4[Zn(NH2)4](NH2)2

Single crystals of Li-4[Zn(NH2)(4)](NH2)(2) were obtained from Li and Zn under ammonothermal conditions (723 K and 1.58 kbar). Li-4[Zn(NH2)(4)](NH2)(2) (C222(1), a = 5.0005(3) angstrom, b = 15.5410(8) angstrom, c = 10.0712(5) angstrom, Z = 4) represents a new possible intermediate in a conceivable ammonothermal synthesis of the semiconductor Zn3N2. Single crystal X-ray diffraction results, thermal analysis, Raman and IR spectra of tetralithium tetraamido zincate diamide are provided and discussed. Crystal structure data justify a description as CaF2 superstructure variant. Large distances in the crystal structure as well as the intensity and half-width of the bands in Raman and IR spectra indicate the absence of significant hydrogen bonds. Upon heating Li-4[Zn(NH2)(4)](NH2)(2) decomposes via intermediate formation of LiZnN, LiNH2 and Li-2(NH) to finally provide pure Zn.