Anomalous mobility of molecules, structure of the guest sublattice, and transformation of tetra- to paranatrolite

The structure of the guest sublattice in the structural channels of natrolite zeolites oversaturated with water (also, at high pressures) is established. It was found from¹H NMR spectra that reduction of symmetry and sharply increased mobility of water molecules in paranatrolite and in the high- pressure phase of orthorhombic natrolite follow the same mechanism — half of positions in the structural channels are occupied by ordered water molecules. The other positions are vacant and may be involved in the mechanism of fast diffusion of water molecules. Translated fromZhumal Strukturnoi Khimii, Vol. 38, No. 4, pp. 676–685, July–August, 1997.