Data from: Pressure-induced symmetry changes in body-centred cubic zeolites

Previous work has shown a strong correlation between zeolite framework
flexibility and the nature of structural symmetry and phase transitions.
However, there is little experimental data regarding this relationship, in
addition to how flexibility can be connected to the synthesis of these
open framework materials. This is of interest for the synthesis of novel
zeolites, which require organic additives to permutate the resulting
geometry and symmetry of the framework. Here, we have used high pressure
powder X-ray diffraction to study the three zeolites: Na-X, RHO and ZK-5,
which can all be prepared using 18-crown-6 ether as an organic additive.
We observe significant differences in how the occluded 18-crown-6 ether
influences the framework flexibility – this being dependant on the
geometry of the framework. We use these differences as an indicator to
define the role of 18-crown-6 ether during zeolite crystallisation.
Furthermore, in conjunction with previous work we predict that
pressure-induced symmetry transitions are intrinsic to body-centred cubic
zeolites. The high symmetry yields fewer degrees of freedom, meaning it is
energetically favourable to lower the symmetry to facilitate further
compression.