Variability in Exchange Ion Position in Smectite: Dependence on Interlayer Solvent

Abstract

Abstract--Full and reduced charge smectite saturated with Na(I), Ca(II), Cu(II), or tetralkylammonium ions were s&ollen by a series of solvents of various bulk physical properties. In the full charge smectites, swelling occurred in all solvents regardless of the exchange ion or the initial water content. Charge differences did not usually result in differential swelling of the smectite. Little correlation was found between the degree of swelling and the Gutmann donor numbers, bulk dielectric constants, bulk surface tensions, or dipole moments of the solvents. The intensities of the high field Fe(III) resonance (9 = 3.6) in the esr spectra of full charge smectite swollen in various solvents reflected variability in exchange ion positions and depended upon the Gutmann donor number of the solvent. Considerable variety in the stereochemistry of Cu(II)-solvent complexes was revealed by esr spectra of the swollen systems.

Effects of Temperature on the Sorption of Lanthanides by Montmorillonite

“…The distinct 15.2-A 001 spacing common to all three Ln-clays is comparable to the 15.0-A and 15.2-~ spacings recorded for Mg-and Ca-montmorillonite, respectively (Berkheiser and Mortland, 1975;McBride et al, 1975b). Both alkaline earth metals have a hydration sphere in an octahedral configuration.…”

“…Both alkaline earth metals have a hydration sphere in an octahedral configuration. In the presence of a negative potential arising from octahedral substitution, these complexes orient themselves in the interlayer with two opposite vertices on a perpendicular line to the clay layers (Berkheiser and Mortland, 1975). This orientation, while not providing a maximum number of water ligand-surface oxygen interactions, places the axial waters close to octahedral charge sites in the silicate framework (hexagonal hole).…”

“…When direct cation-surface oxygen contact occurs, the charge imbalance shows a marked decrease. Thermogravimetric analyses by Berkheiser and Mortland (1975) show a direct parallel between cation hydration energy and the number of water molecules coordinated to the cation. Initial water loss from a fully expanded hydrated clay always affects hydrogen bonding between interlayer waters and not direct linkages to surface oxygens.…”

Reactivity of Adsorbed and Structural Iron in Hectorite as Indicated by Oxidation of Benzidine

“…It is very similar to the orientation-dependence of the Fe 3+ signal in Upton montmorillonite (Berkheiser and Mortland, 1975) but is in the opposite sense. The higher field shoulder appears for the • rather than II orientation of the hectorite film relative to the magnetic field.…”

The I.R. Spectra of Dimethyl Sulfoxide Adsorbed on Several Cation-Substituted Montmorillonites

“…Although infrared spectroscopy was cited in the latter study, no spectra were illustrated for any DMSO-clay complexes. Berkheiser and Mortland (1975) studied the variability in the exchange position in smectite using various montmorillonites swelled by a series of solvents including DMSO. In this study, we will report the infrared spectra of several homoionic montmorillonite-DMSO complexes, and interpret them in terms of the species present in the clay films.…”