Center for Advanced Scientific Computing and Modeling, University of North Texas, Denton, TX 76203, USA.
J Phys Condens Matter. 2010 Nov 10;22(44):445503. doi: 10.1088/0953-8984/22/44/445503. Epub 2010 Oct 22.
Computational studies of nickel carbides, particularly Ni(2)C, are scarce. A systematic density functional theory study is reported for Ni(2)C, along with NiC and Ni(3)C, to understand the stability and electronic structure of nickel carbides of varying stoichiometry. A comprehensive study was executed that involved 28 trial structures of varying space group symmetry for Ni(2)C. An analysis of the electronic structure, geometry and thermodynamics of Ni(2)C is performed, and compared with that for Ni(3)C and NiC as well as several defect structures of varying composition. It is found that the most stable ground state arrangement of Ni(2)C exists within a simple orthorhombic lattice and that it has metallic character. The calculated formation energies (kcal mol(-1)) of NiC, Ni(2)C, and Ni(3)C are 48.6, 7.9 and 6.4, respectively.
镍碳化物的计算研究，特别是 Ni(2)C，很少见。本文采用系统的密度泛函理论研究了 Ni(2)C、NiC 和 Ni(3)C，以了解不同化学计量比的镍碳化物的稳定性和电子结构。这项综合研究涉及 28 种不同空间群对称性的 Ni(2)C 试验结构。对 Ni(2)C 的电子结构、几何形状和热力学进行了分析，并与 Ni(3)C 和 NiC 以及几种不同组成的缺陷结构进行了比较。结果表明，Ni(2)C 的最稳定基态排列存在于简单的正交晶格中，具有金属性质。NiC、Ni(2)C 和 Ni(3)C 的计算形成能（kcal mol(-1)）分别为 48.6、7.9 和 6.4。
