Electrical conductivity of montmorillonite as a function of relative humidity: La-montmorillonite

The conductivity of La-montmorillonite was measured in the domain of water relative pressures (p/p(0)) of <1, and compared with the conductivites of Li- and Na-montmorillonite. La-montmorillonite shows smaller conductivity over the whole range of p/p(0) studied. To explain this, theoretical considerations of the poloarizing power and of the local stacking order induced by the exchangeable cation were addressed.