Cs-Mg-H合金的形成能力与成键机制研究

Formation ability and bonding mechanism of Cs-Mg-H alloy

采用基于密度泛函理论第一性原理的Vienna Abinitio Simulation Package(VASP)软件研究了CsMgH3,Cs4Mg3H10和Cs2MgH4氢化物的晶体结构、反应焓和电子结构.结果表明CsMgH3,Cs4Mg3H10和Cs2MgH4都能直接由单质Cs和Mg在H2中反应生成,其中Cs4Mg3H10的形成能力最强;态密度和电荷密度的分析与讨论表明了Mg和H的成键机制为离子键伴随着显著的共价键.

Theoretical study of structure, reaction enthalpies and electronic structure of the CsMgH3, Cs2MgH4 and Cs4Mg3H10 compounds were performed using the first-principles method based on the density functional theory with generalized gradient approximation. The reaction enthalpies of CsMgH3, Cs2MgH4 and Cs4Mg3H10 showed that the ternary hydrides could be synthesized by direct reaction between Cs and Mg in hydrogen atmosphere, and formation ability of Cs4Mg3H10 was more strong than CsMgH3 and Cs2MgH4. The obtained densities of states and charge density distribution were analyzed and discussed to assess the microscopic mechanism of bond in the compounds. The character of ionic bonds with noticeable covalence bonds between Mg and H was discovered.