Abstract: The slab microstructure of layered double hydroxide(LDH) with n(Mg)/n(Al)=3 is studied via density functional theory at the B3PWP91/Lanl2dz level. The optimized geometric parameters and the simulated XRD patterns of hydrotalcite are in agreement with experimental results. The structural simulations of hydrotalcite show that the host layers stack along the c-axis according to space group R3m, a=1.2552 nm, c=2.3400 nm. On the basis of the stacking multilayer model, the carbonate anion is introduced into the interlayer space and one special cluster structure is obtained through optimization under the condition of keeping space group R3m. The computation results indicate that the interlayer spacing of hydrotalcite with removed crystal water is 0.7260 nm. The changes of bond parameters of cluster suggest that there are strong supramolecular interactions between the slabs and anion.

Key words: Layered double hydroxide, Density functional theory, XRD simulation, Space group