A periodical model of Mg₃Al-LDH-Cl-nH₂O (n＝0～2) has been proposed. The electronic structure, bond character and electron screening effects of interlayer H₂O have been investigated by analyzing the atomic orbital populations, Mulliken charge population, Mulliken bonding population and density of state (DOS) using CASTEP (GGA/PBE) method. The results showed that both electrovalent bonds and covalent bonds have formed in host layer. The main part of interaction between host layer and interlayer guest was electrostatic interaction. While hydrogen bonding interaction dominated the interaction between guest anions and guest water molecules. The electron screening effects of interlayer H₂O have an important influence on interlayer anions and layer bivalent metal ions. Electrovalent parts of host layer and covalent parts of interlayer increased with the number of interlayer water molecule.

Key words: layered double hydroxides, electronic structure, bond character, density functional theory