日本ゼオライト学会　刊行物 Publication of Japan Zeolite Association

X-ray powder diffraction methods are the simplest ones by which we can obtain a useful piece of information on the structure of a crystal, and are used in many laboratories. Diffractions which arise from reciprocal lattice points distributed in a three-dimensional space are recorded linearly in an X-ray powder diffraction diagram. Then, it is usually very difficult to obtain some information on the structure from powder date, because of the overlaps of reflections.

A profile fitting technique is applied to resolve the overlapped reflections in a powder diagram, and the position, the intensity, and the shape of each reflection are precisely determined. Lattice constants of heulandite-clinoptilolite group zeolites and the amounts of the amorphous phase in pottery can be determined precisely by using the positions and the intensities resolved in this way. Precise lattice parameters of a very small quartz crystal, 50 µm in diameter, can be also determined by applying a profile fitting technique to a powder diagram obtained by using a Gandolfi camera.