Synthesis and Characterization of Multi-Component Metal Nitrides

在Li_3 N-Mg_3 N_2体系中制备了具有反萤石型结构的三相。采用氮空位模型对（Li_xMg_<1-x>）_3N_<2-x>（O&lt;x&lt;0.20）和（Li_xMg_<1-x>）_2N_（2-x）2/3&gt;（0.5&lt;x&lt;0.6）的X射线粉末衍射图进行了Rietveld分析。LiMgN中的Li和Mg原子在正交晶胞中有序排列。对于（Li_<1-x>Ni_x）_3N固溶体，随着Ni含量x的增加，a轴长度增加，c轴长度减小。在x=0-0.20下观察到半导体行为，并且在x=0.25下制备的样品显示出金属导电性，这表明电子的离域。在Li-Fe-N体系中，合成了一种新的氮化物。Rietveld分析表明其化学式为Li_7FeNi_3<3.75>。该化合物为立方晶系，空间群为（I-43 m），a=9.782 π，具有反萤石型超结构。Li_7FeN_3<3.75>具有反铁磁性（T_N= 40 K），发现了六种新化合物Ba_Cu_3In_4N_5，Ba_<14>Cu_2In_4N_7，Sr_8Cu_3In_4N_5，Ba<0.73>_Sr_<0.28>CuN，Ba_<4.72>6In_N_3和Ba_<19>In_9N_9，在每种化合物中，N原子被Ba或Sr和/或Cu原子包围，并位于金属原子的N原子中心八面体中。这些八面体共享顶点、棱和面，在Ba_8Cu_3In_4N_5和Sr_8Cu_3In_4N_5中形成隧道结构，在Ba_6In_N_3中形成三维网络<4.72>结构，在Ba_<14>Cu_2In_4N_7、Ba_<0.73>Sr_<0.28>CuN和Ba_<19>In_9N_9中形成层状结构。Ba_8Cu_3In_4N_5和Sr_8Cu_3In_4N_5单晶具有金属导电性。

Three phases with antifluorite-type related structures were prepared in the Li_3N-Mg_3N_2 system. The Rietveld analyses for the X-ray powder diffraction patterns was carried out with nitrogen vacancy models for (Li_xMg_<1-x>)_3N_<2-x>(O<x<0.20) and (Li_xMg_<1-x>)_2N_<(2-x)2/3>(0.5<x<0.6). Li and Mg atoms in LiMgN are arranged orderly in the orthorhombic unit cell. For (Li_<1-x>Ni_x)_3N solid solution, the a-axis length increased and the c-axis length decreased with increasing Ni content x. The semiconducting behavior was observed at x=0-0.20 and the sample prepared at x=0.25 showed metallic conductivity that indicated delocalization of electrons. In the Li-Fe-N system, a new nitride was synthesized. The chemical formula suggested by Rietveld analysis was Li_7FeNi_<3.75>. This compound crystallizes in a cubic cell, space group (I-43m), a=9.782Å, and has an antifluorite-type related superstructure. Li_7FeN_<3.75> showed antiferromagnetism (T_N=40K).Six new compounds BasCu_3In_4N_5,Ba<14>Cu_2In_4N_7,Sr_8Cu_3In_4N_5,Ba<0.73>Sr<0.28>CuN, Ba_6In_<4.72>N_3 and Ba_<19>In_9N_9 were found. In each compound, N atoms are surrounded by Ba or Sr and/or Cu atoms, and situated in the N atom centered octahedron of the metal atoms. These octahedra share apexes, edges, and faces, forming tunnel structures in Ba_8Cu_3In_4N_5 and Sr_8Cu_3In_4N_5,a three-dimensional network in Ba_6In_<4.72>N_3,and layered structure in Ba_<14>Cu_2In_4N_7,Ba_<0.73>Sr_<0.28>CuN and Ba_<19>In_9N_9. The Ba_8Cu_3In_4N_5 and Sr_8Cu_3In_4N_5 single crystal exhibited metallic conductivity.