Inclusion complexes of zeolites. Part 1.—Inclusion complexes of zeolite 4A with silver nitrate and alkali nitrates

Abstract

The structural properties of inclusion complexes of zeolite 4A with alkali nitrates and silver nitrate have been investigated from the point of view of the state and position of the included component. The crystal structures of alkali nitrate complexes, Li₁₂A˙9.8LiNO₃˙9.3H₂O and Na₁₂A˙10NaNO₃˙6.6H₂O, have been solved and refined in the cubic space-group Pm3m; at 24 °C the unit-cell constants are: a₀= 12.075(1)Å and a₀= 12.295(1)Å, respectively. For Ag₁₂A˙9.5AgNO₃˙5.9H₂O complex the unit-cell constant is a₀= 12.340(1)Å. On the basis of i.r. and X-ray structure analyses it is found that the included nitrate in zeolite cages exists partially as a nitrate ion and partially as a nitrato complex. The nitrate ions, situated near the S6R, are in coordination with the zeolite counter-ion and also with the closest included cations. The nitrato ions, situated near the S8R, are in coordination with included cations only.