Abstract
Species P has similar X-ray powder patterns to those for gismondine and phillipsite. As for polycrystalline zeolitic materials with low crystallinity, such as so called species P, the diffraction peaks from the different planes, whose d-spacing are closely resemble, overlap with each other, and show only a few broad lines. The structural differences between phillipsite and gismondine are discussed based on the reported space groups and X-ray powder data, and the sine qua non for the X-ray powder data for phillipsite was deduced.
