Mica-Type Layer Silicates with Alkylammonium Ions

Armin Weiss
Chemisches Institut der Universität Heidelberg, Germany

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-alkylammonium compounds, for instance, the sum (n-CxH2x+1NH3++n-CxH2x+1Y) per (Si, Al)4O10 is equal to 2.0 (Y=OH, Cl, Br, NH2, COH, CONH2, 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 alkylammonium-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.

Clays and Clay Minerals; 1961 v. 10; no. 1; p. 191-224; DOI: 10.1346/CCMN.1961.0100116
© 1961, The Clay Minerals Society
Clay Minerals Society (www.clays.org)