高等学校化学学报

高等学校化学学报 ›› 1997, Vol. 18 ›› Issue (3): 429.

• 论文 • 上一篇    下一篇

关于立方晶体Mg2NiH4结构中复合体[NiH4]的几何构型

廖孟生, 张乾二   

  1. 厦门大学化学系, 厦门, 361005
  • 收稿日期:1996-04-21 出版日期:1997-03-24 发布日期:1997-03-24
  • 通讯作者: 廖孟生, 男, 32岁, 博士, 副教授.
  • 作者简介:廖孟生, 男, 32岁, 博士, 副教授.
  • 基金资助:

    国家教育委员会留学回国人员经费资助

On the Configuration of the [NiH4] Complex in Cubic Mg2NiH4 Structure

LIAO Meng-Sheng, ZHANG Qian-Er   

  1. Department of Chemistry, Xiamen University, Xiamen, 361005
  • Received:1996-04-21 Online:1997-03-24 Published:1997-03-24

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摘要： 用相对论密度泛函法研究了立方晶体Mg2NiH4结构中复合体[NiH4]的几何构型.晶体的环境用一个“切断”(Cut－off)的Madelung势来模拟.计算中分别假设了一个平面四边形NiH和一个四面体NiH的构型.对于平面四边形构型,计算的Ni-H键长及力常数与实验值相符;但对四面体计算的键长太短而力常数太大.研究结果表明;立方Mg2NiH4结构中对复合体[NiH4]的选择是平面四边形构型,而不是四面体.

关键词: 构型, 镁镍氢化物, 密度泛函计算, 晶体场

Abstract: The configuration of the [NiH4] complex in cubic Mg2NiH4 structure has been investigated by using relativistic density-functional method The crystalline environment was simulated by a cut-off type Made1ung potential.Asquare planar configuration of NiH42-and a tetrahedral configuration of Ni44-Hare assumed, respectively in the calculations.For the square planar configuration, a good agreement of the calculated bond length and force constant with experimental ones was obtained.However, the calculation on the tetrahedral configuration yielded too short Ni-Hbond length and too large Ni-H42-force constant.The comparison between the calculated results and experimenta1 ones gives a clear preference of the square NiH44-configuration over the tetrahedral NiHconfiguration in the cubic Mg2NiH4 structure.

Key words: Configuration, Magnesium nickel hydride, Density-functional calculations, Crystal field

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