Abstract
Periodic ab initio Hartree-Fock LCAO calculations have been carried out on the two dimensional sheet of SiO4 tetrahedra, representing one of the basic constituting units of layer silicates, using Huzinaga's DZP basis sets. The influence of the basis set on the chemical bonding picture is characterized by Mulliken atomic charges and by electron density maps. Silicon atomic charges ∼ +1.6 ¦e¦ are more realistic than those ∼ +2.4 ¦e¦ reported for smaller basis sets. The silicon d orbital population is found to be 0.6 in close agreement with molecular data. Electron density maps indicate the absence of charge density in the center of the ditrigonal cavity. The charge buildup of nonbonding basal oxygen orbitals is directed mainly downwards perpendicular to the sheet plane.
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Benco, Ľ., Smrčok, Ľ. Ab initio calculated electron densities for tetrahedral sheet [H2Si2O5]∞ in phyllosilicates. Phys Chem Minerals 21, 401–406 (1994). https://doi.org/10.1007/BF00203298
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DOI: https://doi.org/10.1007/BF00203298