Matì Ere Condensée, Chimie Et Organisation

The effect of temperature in the range of 0–150 8C was studied for homoionic montmorillonite clays with Na and Csqq compensating ions in low hydration states. Both static and dynamic information concerning the interlayer ions and water moleculeswas obtained by Monte Carlo and molecular dynamics. Principal structural changes were limited to the water phase, markeddifference was observed in the modes of diffusion of Cs and Na ions. Cs ion exhibited a clear site-to-site diffusion betweenqqq sites allowing coordination to six oxygen atoms of the clay sheets, this behaviour persisted to high temperatures. Preferential sitesfor the Na counterion were significantly less well-defined, even at low temperatures. Water phase showed similar behaviour inq the NayCs-monohydrated systems, a rapid approach to bulk dynamics was seen in the transition from monohydrated to bihydratedNa-montmorillonite.2004 Elsevier Ltd. All rights reserved.