Illite rectorite

Ca and Mg is inversed for vermiculite and montmorillonite (Levy and Shainberg, 1972). Further, the natural mica-beidellite interlayered minerals (rectorite) are sodi-calcic while the mica-montmorillonite minerals (allevardite) are sodi-potassic. Quite possibly, the site of charge imbalance changes the selectivity coefficients for exchangeable ions. The montmorillonite series of interlayering will produce illite and the beidel-litic series could lead to a paragonitic or possibly calcic mica. 

The other clay mineral, illite, also has some strontium sorption, but the distribution coefficient is about one order of magnitude lower than that of montmorillonite and rectorite. Since, in illite, the layer charge is compensated by non-exchangeable cations (Chapter 1, Table 1.2), cation sorption can takes place only on the deprotonated edge sites. This is the case for tectosilicates (quartz, cristobalite). 

Rectorite is one of an almost infinite number of randomly mixed layer clays (411. collectively called illites, which include several other ordered interstratified varieties, including chlorite, corrensite and allevardite. Rectorite has the advantages of a mica and a smectite, in that alternate interlayers are expanding and non-expanding. It may be viewed as an ordered synthetic mica-montmorillonite (SMM) in the nomenclature familiar to catalytic... 

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