钙空位12CaO·7Al_2O_3晶体稳定性的计算机模拟

Computer simulation of crystal stability of 12CaO·7Al_2O_3 with calcium vacancy

通过Materials Studio软件在建立完整的12CaO·7Al2O3晶体结构模型的基础上逐渐减少Ca原子数,使其形成Ca空位,对钙空位量为0~1.00的12CaO·7Al2O3晶体结构进行几何优化模拟,计算其晶格参量、晶体自由能、化学键布居数及键长等。结果表明:Ca空位对12CaO·7Al2O3晶体结构的稳定性有显著影响,随着Ca空位量的增加,12CaO·7Al2O3晶体晶格参量和晶胞体积逐渐降低,自由能逐渐增加,O—Ca键稳定性变差;当Ca空位量增加到0.75和1.00时,O—Ca键种类由4种减少到3种,且键长增大,从而导致12CaO·7Al2O3晶体的稳定性逐渐降低;分别合成钙空位量为0、0.50和1.00的12CaO·7Al2O3晶体,其在碳酸钠溶液中的分解率随着钙空位量的增加而增加,晶体稳定性与晶体学模拟结果相吻合。

The geometry optimization simulation of 12CaO·7Alcrystal with different calcium atom vacancies from 0to 1 was performed by gradually decreasing calcium atoms based on the establishment of complete crystal structure with Materials Studio software, the corresponding lattice parameters, free energy, chemical bond population bond length were also calculated. The results show that the calcium atom vacancy has a significant effect on the stability of 12CaO·7Alcrystal structure. The lattice parameter and the cell volume decrease while the free energy increases with the increase of calcium atom vacancy in 12CaO·7AlThe main bonds of 12CaO·7Alof are OCa, and the number of OCa decreases from 4 to 3, and bond length increase when the calcium vacancy increases to 0.75 and 1.00, resulting in the stability decrease of 12CaO·7AlThe 12CaO·7Alcrystals with calcium atom vacancies of 0, 0.50 and 1.00 were synthesized respectively, and the decomposition rate of 12CaO·7Alin sodium carbonate solution increases as the calcium vacancy increases, the crystal stability of which is in accordance with the computer simulation results.