Preparation of Multicomponent Nitrides and their Crystal Chemstry

尝试了以叠氮钠(NaN3)为厌氮源，金属钠(Na)为助熔剂制备多元氮化物。金属源用NaN3和Na密封在不锈钢管状容器中，内壁覆盖一层Nb。将该试管放入有氩气的电炉中，在750ﾟC下加热。加热后，将试管冷却至室温。用液氨清洗钠熔剂。为此，设计了一种H形电解槽。用这种方法制备了氮化镓锶镓氮化物单晶。晶体大小小于1毫米，薄片，黄色，透明。X-射线单晶结构分析表明，该化合物具有正交对称性(晶胞参数：α=5.9579(12)，b=10.285(2)，c=9.557(2)A，空间群PnNa)。Sr3Ga2N4与Sr3Al2N4和Ba3Ga2N4是同结构的。Ga原子由四个氮原子配位形成四面体。四面体共享两条边，形成一维链。锶原子被六个氮原子包围。在Ba-Ti-N系中也获得了红色透明单晶，而在Sr-TiN系中则没有。在含稀土元素的系统中，获得了二元氮化物的混合物，不能合成多组分氮化物。

Preparation of multi-component nitrides was attempted by using sodium azide (NaN3) as anitrogen source and sodium metal (Na) as a flux. Metal sources were sealed with NaN3 and Na in a stainless-steel tube container in which the inner wall was covered with a niobium sheet. This tube was placed in an electric furnace with argon gas and heated at 750ﾟC.After the heating, the tube was cooled to room temperature. The Na flux was washed with liquid ammonia. An H-shape cell was designed for this process. By using the present method, single crystals of strontium gallium nitride, Sr_3Ga_2N_4 were prepared. The crystals were below 1 mm in size, thin platelet, yellow, and transparent. X-ray single crystal structure analysis revealed that this compound has an orthorhombic symmetry (lattice parameters : alpha= 5.9579(12) , b = 10.285(2) , c = 9.557(2) A, space group P nna). Sr_3Ga_2N_4 is isostructural with Sr_3Al_2N_4 and Ba_3Ga_2N_4. Ga atoms were coordinated by four nitrogen atoms and form tetrahedra. The tetrahedra share two edges and make a one-dimensional chain. Strontium atoms are surrounded by six nitrogen atoms. Red color transparent single crystals were also obtained in the system of Ba-Ti-N, but not in the Sr-Ti N.Mixture of binary nitrides were obtained and multi-component nitrides could not be synthesized in the systems including rare-earth elements.