Have the structure and space-group of A-type zeolite been correctly assigned?
Abstract
The results of recent electron diffraction and solid-state n.m.r. studies are incompatible with the accepted space-group of zeolite A (idealized formula M+12Al12Si12O48.27H2O); it is argued that the space-group is Pm3 when Si/Al is unity, and Fm3 when this ratio deviates from unity.