Structure determination from powder diffraction data: past, present and future challenges

Abstract

Structural information is crucial for understanding and tailoring the materials properties. When the materials are available only in the polycrystalline form, powder diffraction is the method of choice for structure determination. Compared to the single crystal data, the powder pattern contains less information due to the overlap problem and the reduction of the information content is even larger if only the low resolution data are available. Several data analysis approaches are available to address this problem, including reciprocal, direct and dual space methods. They are discussed and illustrated by a number of examples, including cases where other techniques, such as IR and NMR spectroscopy, electron microscopy and crystal-chemical knowledge have to be applied to solve the structure.

Structure elucidation of a complex CO2-based organic framework material by NMR crystallography

“…This highlights the fact that PXRD patterns are sensitive to very small structural changes, such that if the candidate structure is not within a few fractions of an angstrom in rmsd from the correct structure then poor agreement will always be obtained. 85 Notably, changes in the unit cell parameters induce large changes in the PXRD line positions and intensities, and since indexing failed here it is unlikely that the candidate structures have exactly correct cell parameters. This is especially true if we recall that that the materials here may have some dispersion in the chain lengths and the hydration states that would almost certainly induce changes with respect to the model cells predicted here.…”

From Solid‐State Structure and Dynamics to Crystal Engineering

“…The net result has been not only a broadening of the field of solid‐state chemistry as a whole, with significant overlaps with materials chemistry, nanotechnology and medicine, but also a new impulse, in a synergistic way, to crystallography, both in experimental methods and in computational modelling (e.g. structural determination from powder data, surface diffractometry, crystal structure prediction, etc. ).…”

Modeling of the Crystal Structure of Platinum Metal’s Complex Compounds by Using Parallel Computing Based on Genetic Algorithms and X-ray Diffraction Data

“…С ростом мощности компьютеров эффективными для этой цели ста-ли методы глобальной оптимизации структуры в прямом пространстве [4,5], основанные, по-добно методу Ритвельда, на моделировании экспериментальных дифрактограмм, в частности генетические алгоритмы (ГА) [6]. ГА имитируют биологическую эволюцию, т.е.…”