物理化学学报 >> 1996, Vol. 12 >> Issue (03): 245-251.doi: 10.3866/PKU.WHXB19960311

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C2近邻环境对金属碳化物电子结构的影响

陈学安,赵凌,李言,陈本明,傅亨   

  1. 中国科学院化学研究所，北京 100080
  • 收稿日期:1995-07-26 修回日期:1995-10-10 发布日期:1996-03-15
  • 通讯作者: 陈学安

Effect of the C2 Near-neighbor Environment on the Electronic Structures of Metal Carbides

Chen Xue-An,Zhao Ling,Li Yan,Chen Ben-Ming,Fu Heng   

  1. Institute of Chemistry,Academia Sinica,Beijing 100080
  • Received:1995-07-26 Revised:1995-10-10 Published:1996-03-15
  • Contact: Chen Xue-An

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摘要：

对一系列金属碳化物簇进行了DV－Xα分子轨道计算，探讨了C2配位环境对电子结构的影响. 计算结果表明，在La6C215+簇中，La的5d和C的2p带分开，键基本上是离子性. 当La原子被Ni取代形成La4Ni4C216+簇之后，Ni的3d和C的2p带几乎完全重叠，表明了强的Ni－C共价作用．此外．在Sc5Ni4C218+簇中，除Ni－C和C－C共价作用外，还存在着强的金属-金属键．

关键词: C2近邻环境, 金属碳化物簇, 电子结构, DV-Xa

Abstract:

DV-Xa molecular orbital calculations have been performed on a series of metal carbide clusters to examine the effect of the C2 coordination environment on the electronic structures. It was found that the La 5d and C 2p bands are well-separated and the bonding is nearly ionic character in La6C215+ cluster. The covalency becomes more important if the La atoms in La6C15+2 are replaced by Ni to form the La4Ni4C216+cluster where the Ni 3d and C 2p bands are almost completely overlapped, indicating a strong Ni-C covalent interaction. Moreover, in Sc5Ni4C218+ cluster, besides the Ni-C and C-C covalent interactions there exist also the strong metal-metal bonds due to the two-dimensional Ni-Ni network.

Key words: C2 near-neighbor environment, Metal carbide clusters, Electronic structure, DV-Xa