ON THE CHEMISTRY OF KANEMITE [NAHSI2O5.3 H2O](X)

Starting from delta-Na2Si2O5 Kanemit was prepared by a direct exchange of Na+ by H+ in water containing reaction mixtures. By Si-29-, Na-23- and H-1-MAS-NMR investigations Kanemit was characterized as a layersi licate [NaHSi2O5 ... 3 H2O]. By thermal treatment as well as by dehydr ation at room temperature under vacuum conditions a monohydrate is for med in which the layerstructure remains nearly unchanged. At temperatu res between 100 and 110 degrees C under normal conditions a hydrate ph ase of the composition [NaHSi2O5 . 0.25 H2O](x) is prepared in which a changed silicate-layerstructure exists.