Mica-Type Layer Silicates with Alkylammonium Ions

Abstract

Abstract More than 8000 different derivatives of mica-type layer silicates (muscovite, biotite, illite, vermiculite, beidellite, montmorillonite) with alkylammonium ions and different organic molecules as swelling liquids were prepared and characterized analytically by X-ray and chemical methods. The following results have been discussed in some detail. Layer-lattice compounds are formed in simple stoichiometric relations. In n -alkyl-ammonium compounds, for instance, the sum ( n -C x ,H 2 x +1 NH 3 + + n -C x H 2 x +1 Y) per (Si, Al) 4 O 10 is equal to 2.0 (Y = OH - , Cl - , Br - , NH 2 - , COH - , CONH 2 - , CN - ). The layer distance of the pure n -alkylammonium derivatives enables one to determine the charge density in the silicate layers. But in soils the ability of humic acids to undergo two-dimensional intracrystalline swelling and to react with alkylammonium ions must also be considered. The properties of n -alkylammonium layer silicates are similar to those of alkyl-ammonium-uranium micas and of swelling vanadates (e.g. hewettite and pascoite). The swelling properties of alkyl-(α, ω )-diammonium ions are markedly influenced by the opportunities for hydrogen bonding. Mica-type layer silicates may show catalytic properties like protease or oxidase with ammonium ions, which are of general interest.