Open AccessAb initio structural simulation and electronic structure of lithium imide
Author(s) -
Yu Da-Long,
Yuhong Chen,
Cao Yi-Jie,
CaiRong Zhang
Publication year - 2010
Publication title -
wuli xuebao
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.199
H-Index - 47
ISSN - 1000-3290
DOI - 10.7498/aps.59.1991
Subject(s) - tetragonal crystal system , materials science , crystal structure , density functional theory , crystallography , ab initio , imide , pseudopotential , wannier function , electron localization function , lithium (medication) , hydrogen bond , ionic bonding , covalent bond , chemistry , computational chemistry , atomic physics , ion , molecule , condensed matter physics , physics , electron , medicine , organic chemistry , endocrinology , quantum mechanics , polymer chemistry
The crystal structure and the locations of the hydrogen of lithium imide Li2NH are studied by first-principle plane wave pseudopotential method based on the density function theoryDFT. Three models are used to investigating the effects of the Li, N and nearest-neighbor N—H bonds to N—H bond orientation, respectively. The calculated results show that Li2NH crystal can be described by a layered tetragonal crystal P42 structure. Four N—H bonds of each conventional cell align in two layers. The two imide groups in the same layer prefer to be antiparallel and the imide groups in the nearest-neighbor layers tend to be vertical. The density of states DOS and the electron local function ELF analysis show strong ionic interaction between the Li and N—H dimmer, while the bonding between the N and H has covalent character. Our P42 structure of Li2NH crystal yields a hydrogen storage Li2NH2+H2/LiNH2+LiH reaction enthalpy of 69.6 kJ/mol H2 at T=0 K, in good agreement with experimental reports of 66 kJ/mol H2 for this reaction.