The present invention relates to a silicoaluminophosphate molecular sieve
comprising at least one intergrown phase of molecular sieves having AEI
and CHA framework types, wherein said intergrown phase has an AEI/CHA
ratio of from about 5/95 to 40/60 as determined by DIFFaX analysis, using
the powder X-ray diffraction pattern of a calcined sample of said
silicoaluminophosphate molecular sieve. It also relates to methods for its
preparation and to its use in the catalytic conversion of methanol to
olefins.
