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水滑石层间阴离子热稳定性、离子交换性能等物化性质与LDHs材料主客体间以静电作用为主的超分子作用密切相关,但LDHs材料的晶格能计算目前仍相当困难。本文以层间阴离子作为负电荷基团、对应等电量氢氧化物层板作为正电荷基团,构建水滑石(LDHs)主客体静电作用模型。采用晶体化学第二定律,对LDHs材料晶格能进行理论计算,并与层间阴离子交换性能以及热稳定性等物化性质进行了比较。研究结果表明:改变层间阴离子种类,晶格能大小次序为Mg3Al-F-LDHs>Mg3Al-OH-LDHs>Mg3Al-Cl-LDHs>Mg3Al-Br-LDHs>Mg3Al-I-LDH,Mg3Al-CO3-LDHs>Mg3Al-CrO4-LDHs>Mg3Al-SO4-LDHs>Mg3Al-NO3-LDHs,与文献报道的LDHs层间阴离子交换性能相一致。改变层板金属离子比例,计算得到晶格能大小顺序为Mg2Al-CO3-LDHs>Mg3Al-CO3-LDHs>Mg4Al-CO3-LDHs,与层间碳酸根热稳定性相一致。改变层板金属离子种类,预测得到层间碳酸根热稳定顺序为:Mg3Al-CO3-LDHs>Cu3Al-CO3-LDHs>Ni3Al-CO3-LDHs>Zn3Al-CO3-LDHs-Co3Al-CO3-LDHs>Fe3Al-CO3-LDHs>Mn3Al-CO3-LDHs>Cd3Al-CO3-LDHs>Ca3Al-CO3-LDHs;Mg3Al-CO3-LDHs>Mg3Ni-CO3-LDHs-Mg3Co-CO3-LDHs-Mg3Fe-CO3-LDHs>Mg3Cr-CO3-LDHs。本文中对于LDHs材料晶格能的计算,为其热稳定性与离子交换性能的预测提供了理论依据。此外,LDHs材料的静电作用模型构建方法,对于其他层状主客体材料晶格能计算也有较高的参考价值。
Hydrotalcite interlayer anion thermal stability, ion exchange properties and other physicochemical properties and LDHs host-guest interaction between the main role of the supramolecular interactions are closely related, but the LDHs lattice energy calculation is still quite difficult. In this paper, the interlayer anion as a negative charge group, corresponding to the equivalent charge of the hydroxide layer as a positive charge group, to build the electrostatic interaction model of hydrotalcite (LDHs) guest and guest. The second law of the crystal chemistry was used to calculate the lattice energy of the LDHs material, and the physical and chemical properties of the interlayer anion exchange properties and thermal stability were compared. The results show that the order of the lattice energies is Mg3Al-F-LDHs> Mg3Al-OH-LDHs> Mg3Al-Cl-LDHs> Mg3Al- LDHs> Mg3Al-CrO4-LDHs> Mg3Al-SO4-LDHs> Mg3Al-NO3-LDHs, which is consistent with the anion exchange performance of LDHs reported in the literature. By changing the proportion of metal ions in the plate, the order of the lattice energies is calculated as Mg2Al-CO3-LDHs> Mg3Al-CO3-LDHs> Mg4Al-CO3-LDHs, which is consistent with the thermal stability of interlayer carbonate. The order of thermal stability of interlayer carbonates was predicted by changing the species of interlayer metal ions: Mg3Al-CO3-LDHs> Cu3Al-CO3-LDHs> Ni3Al-CO3-LDHs> Zn3Al-CO3-LDHs-Co3Al- CO3-LDHs> Mg3Ni-CO3-LDHs-Mg3Co-CO3-LDHs-Mg3Fe-CO3-LDHs> Mg3Cr-CO3-LDHs> LDHs. In this paper, the calculation of the lattice energy of LDHs material provides a theoretical basis for the prediction of its thermal stability and ion exchange performance. In addition, the construction method of the electrostatic action model of LDHs material is also of high reference value for the calculation of lattice energy of other host-guest materials.