Quantum mechanical calculations of dioctahedral 2:1 phyllosilicates: Effect of octahedral cation distributions in pyrophyllite, illite, and smectite

• DOI: 10.2138/am-2002-0719
• Publication Date: 2015-09-24T13:48:30Z
• Authors: C. Ignacio Sainz-...; Vicente Timón; Vicente Botella; Emilio Artacho; Alfonso Hernández...
• Keywords: Pyrophyllite; Illite; Charge density

The structure of dioctahedral 2:1 phyllosilicates with different interlayer charge was studied theoretically using ab initio calculations. standard Kohn-Sham self-consistent density functional method used in the generalized gradient approximation (GGA), numerical atomic orbitals as basis set, by means SIESTA program. Once had been checked satisfactorily, theoretical study extended beyond systems for which there are experimental information, and structural characteristics were predicted. program shown to be a useful tool studying crystallographic properties 2:1-dioctahedral phyllosilicates. crystal structures pyrophyllite, beidellite, other smectites illites simulated. high, medium, low reproduced. calculated agree main features lattice these minerals. effect cation substitutions octahedral tetrahedral sheets also studied. effects consistent results. Mg2+ cations found have tendency distributed sheet, contrast Fe3+ ions that tend clustered