Fuel Cycle and Isotopes Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6093, USA.
Inorg Chem. 2012 Mar 5;51(5):3332-40. doi: 10.1021/ic300025b. Epub 2012 Feb 23.
Using a new, low-temperature, fluoride-based process, thorium nitride imide of the chemical formula Th(2)N(2)(NH) was synthesized from thorium dioxide via an ammonium thorium fluoride intermediate. The resulting product phase was characterized by powder X-ray diffraction (XRD) analysis and was found to be crystallographically similar to Th(2)N(3). Its unit cell was hexagonal with a space group of P3m1 and lattice parameters of a = b = 3.886(1) and c = 6.185(2) Å. The presence of -NH in the nitride phase was verified by Fourier transform infrared spectroscopy (FTIR). Total energy calculations performed using all-electron scalar relativistic density functional theory (DFT) showed that the hydrogen atom in the Th(2)N(2)(NH) prefers to bond with nitrogen atoms occupying 1a Wyckoff positions of the unit cell. Lattice fringe disruptions observed in nanoparticle areas of the nitride species by high-resolution transmission electron microscopic (HRTEM) images also displayed some evidence for the presence of -NH group. As ThO(2) was identified as an impurity, possible reaction mechanisms involving its formation are discussed.
使用一种新的低温氟化物基工艺，通过中间的氟化铵钍，从二氧化钍合成了化学式为 Th(2)N(2)(NH)的氮化钍。通过粉末 X 射线衍射（XRD）分析对所得产物相进行了表征，发现其晶体结构与 Th(2)N(3)相似。其晶胞为六方晶系，空间群为 P3m1，晶格参数为 a = b = 3.886(1) 和 c = 6.185(2) Å。通过傅里叶变换红外光谱（FTIR）证实了氮化物相中存在-NH。使用全电子标量相对论密度泛函理论（DFT）进行的总能量计算表明，Th(2)N(2)(NH)中的氢原子优先与占据晶胞 1a Wyckoff 位置的氮原子键合。高分辨率透射电子显微镜（HRTEM）图像中在氮化物物种的纳米颗粒区域观察到的晶格条纹中断也显示出-NH 基团存在的一些证据。由于鉴定出二氧化钍是杂质，因此讨论了可能涉及它形成的反应机制。
