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| Orbital Calculations of Kaolinite Surface:on Substitution of Al~(3 ) for Si~(4 ) in the Tetrahedral Sites | |
| 引用本文： | 洪汉烈. Orbital Calculations of Kaolinite Surface:on Substitution of Al~(3 ) for Si~(4 ) in the Tetrahedral Sites[J]. 武汉理工大学学报(材料科学英文版), 2007, 0(4) |
| 作者姓名： | 洪汉烈 |
| 作者单位： | The Faculty |
| 基金项目： | the Key Project of Chinese Ministry of Education(No.107076)，the National Natural Science Foundation of China(40172017)，Calculations performed in Wuhan University of Technology(PC99691149W3733N) |
| 摘 要： | The surface properties of kaolinite were determined using density functional theory discrete variational method(DFT-DVM)and Gaussian 03 program.A SiO_4 tetrahedral hexagonal ring with two Al octahedra was chosen to model the kaolinite crystal.The total density of states of the kaolinite cluster are located near the Fermi level at both sides of the Fermi level.Both the highest occupied molecular orbit (HOMO)and the lowest unoccupied molecular orbit(LUMO)of kaolinite indicate that kaolinite system can not only readily interact with electron-acceptor species,but also readily interact with electron-donor species on the edge surface and the gibbsite layer surface,and thus,shows amphoteric behavior.Substitution of Al~(3 ) for Si~(4 ) in the tetrahedral site linking the vacant Al~(3 ) octahedra does not increase the surface chemical reactivity of kaolinite,while substitution of Al~(3 ) for Si~(4 ) in the tetrahedral site with the apex O linking Al~(3 ) octahedra increase the surface chemical reactivity of the siloxane surface of kaolinite,especially acting as electron donors. Additionally,substitution of Al~(3 ) for Si~(4 ) in the tetrahedral site results in the re-balance of charges,leading to the increase of negative charge of the coordinated O atoms of the AlO_4 tetrahedra,and therefore favoring the formation of ionic bonds between cations and the surface O atoms in the basal plane. |
Orbital Calculations of Kaolinite Surface:on Substitution of Al~(3 ) for Si~(4 ) in the Tetrahedral Sites |
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| HONG Hanlie MIN Xinmin ZHOU Yong. Orbital Calculations of Kaolinite Surface:on Substitution of Al~(3 ) for Si~(4 ) in the Tetrahedral Sites[J]. Journal of Wuhan University of Technology. Materials Science Edition, 2007, 0(4) | |
| Authors: | HONG Hanlie MIN Xinmin ZHOU Yong |
| Affiliation: | HONG Hanlie~1 MIN Xinmin~2 ZHOU Yong~1 |
| Abstract: | The surface properties of kaolinite were determined using density functional theory discrete variational method(DFT-DVM)and Gaussian 03 program.A SiO_4 tetrahedral hexagonal ring with two Al octahedra was chosen to model the kaolinite crystal.The total density of states of the kaolinite cluster are located near the Fermi level at both sides of the Fermi level.Both the highest occupied molecular orbit (HOMO)and the lowest unoccupied molecular orbit(LUMO)of kaolinite indicate that kaolinite system can not only readily interact with electron-acceptor species,but also readily interact with electron-donor species on the edge surface and the gibbsite layer surface,and thus,shows amphoteric behavior.Substitution of Al~(3 ) for Si~(4 ) in the tetrahedral site linking the vacant Al~(3 ) octahedra does not increase the surface chemical reactivity of kaolinite,while substitution of Al~(3 ) for Si~(4 ) in the tetrahedral site with the apex O linking Al~(3 ) octahedra increase the surface chemical reactivity of the siloxane surface of kaolinite,especially acting as electron donors. Additionally,substitution of Al~(3 ) for Si~(4 ) in the tetrahedral site results in the re-balance of charges,leading to the increase of negative charge of the coordinated O atoms of the AlO_4 tetrahedra,and therefore favoring the formation of ionic bonds between cations and the surface O atoms in the basal plane. |
| Keywords: | kaolinite quantum chemistry molecular orbital density of state M(?)lliken charge |
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