(1. 东北大学 多金属共生矿生态化冶金教育部重点实验室，沈阳 110819；
2. 东北大学 冶金学院，沈阳 110819)
摘 要: 建立完整的CaO·SiO2晶体模型并模拟晶体中Ca原子缺失缺陷的形成，对钙硅比为0.91~1.00的CaO·SiO2晶体进行几何优化。运用CASTEP计算其晶格参数、生成焓、布居值及键长、态密度以及差分电荷密度。结果表明：钙缺失量在0~0.09范围内，随着缺失Ca原子缺失量的增多，CaO·SiO2晶体的晶格参数和体积逐渐增大，生成焓逐渐增加；O—Ca键的布居值减小，键长不断增加，在费米能级处的态密度逐渐增加；O 2p与Si 3p轨道之间的杂化作用减弱，赝能隙逐渐变窄；O和Si原子处的局域电荷密度和得失电子数减少，CaO·SiO2晶体的稳定性逐渐下降。合成了钙硅比分别为1.00、0.97、0.94、0.91的CaO·SiO2晶体，其在铝酸钠溶液中的分解率随Ca原子缺失数的增多而增加，稳定性降低，与模拟结果一致。
关键字: CaO·SiO2；钙缺失；晶体结构；稳定性；计算机模拟
（1.Key Laboratory for Ecological Metallurgy of Multimetallic Mineral, Ministry of Education, Northeastern University, Shenyang 110819, China;
2. School of Metallurgy, Northeastern University, Shenyang 110819, China）
Abstract:In order to simulate the crystal defects of CaO·SiO2 caused by Ca atom deficiency, the geometry optimization of CaO·SiO2 with C/S of 0.91-1.00 was carried out. The lattice parameters, formation enthalpy, population, bond length, state density and differential charge density were calculated by CASTEP modular. The amount of calcium deficiency ranges from 0 to 0.09 as the Ca atom deficiency increases, the lattice parameters, volume and formation enthalpy of CaO·SiO2 crystal gradually increase, the population values of O—Ca bonds decrease, the bond length increases, and the state density at Fermi level increases, respectively. Meanwhile, the hybridization between O 2p and Si 3p is weakened and the pseudoenergy gap becomes narrower. The local charge density and electron number of O and Si atoms decrease, which decreases the stability of CaO·SiO2 crystal. The CaO·SiO2 compounds were synthesized when the C/S are 1.00, 0.97, 0.94 and 0.91, respectively, and their decomposition rates in sodium aluminate solution increase with the Ca atom deficiency increasing, which is consistent with the structural stability simulation.
Key words: CaO·SiO2; calcium deficiency; crystal structure; stability; computer simulation
