Exploiting texture to estimate the relative intensities of overlapping reflections

Abstract

Additional information about the relative intensities of reflections that overlap in a powder diffraction pattern can be obtained from a polycrystalline sample in which the crystallites are preferentially oriented. If the data are collected and analyzed appropriately, more single-crystal-like reflection intensities can be extracted, and thereby more complex structures solved. This 'texture method' was implemented initially in reflection mode and its power demonstrated with the solution of the 117-atom structure of the high-silica zeolite UTD-1F. However, the experiment required a minimum of 3 days of synchrotron beamtime per sample. In an attempt to reduce the amount of beamtime needed and to simplify the experiment itself, a transmission mode alternative using an area detector was developed. Details of the sample preparation, data collection and data analysis for both geometries are described. The solution of the structures of the aluminophosphates Mu-9 (R3c, a = 14.0696(1) Å, c = 42.3113(4) Å) and AIPO-M (Pbca, a = 9.7493(1) Å, b = 29.1668(2) Å, c -9.3528(1) Å) using reflection and transmission mode data, respectively, are provided as examples of the method.