Contemporary Advances in the Use of Powder X-Ray Diffraction for Structure Determination

Abstract

Many crystalline solids cannot be prepared in the form of single crystals of sufficient size and/or quality for investigation using single‐crystal X‐ray diffraction techniques, and the opportunity to carry out structure determination using powder diffraction data is therefore essential to understand the structural properties of such materials. Although the refinement stage of the structure determination process can be carried out fairly routinely from powder diffraction data using the Rietveld profile refinement technique, solving crystal structures directly from powder data is associated with several intrinsic difficulties. Nevertheless, substantial progress has been made in recent years in the scope and potential of techniques in this field. This article aims to highlight the types of structural problems for which structure determination may now be tackled directly from powder diffraction data, and contemporary applications across several chemical disciplines are presented. A brief survey of the underlying methodologies is given, with some emphasis on recently developed techniques for carrying out the structure‐solution stage of the structure‐determination process.

Cocristais: uma estratégia promissora na área farmacêutica

“…5,71 A aplicação de fusão seguida de extrusão parece ser uma alternativa promissora para a formação de cocristais onde a instabilidade química não é um problema. 84 Para confirmação da formação de um cocristal e diferenciação em relação a outros cristais multicomponentes, diversas técnicas de caracterização no estado sólido podem ser empregadas, como difração de raios X (DRX), 85,86 análise térmica (Calorimetria Exploratória Diferencial -DSC e Termogravimetria -TGA), 1,86,87 microscopia, 88,89 espectroscopia vibracional (Raman e Infravermelho), 86,90 espectroscopia do estado sólido (Ressonância magnética nuclear do estado sólido -RMNss) 86,91-93 e análise de sorção de umidade. [94][95][96][97] …”

Structural aspects of the metal–insulator transition in BaVS3

“…Eugene Y. Cheung With the advances of direct space strategies for structure solution from powder data [1,2], and in particular the success of the Genetic Algorithm method [3,4], a fundamental question on what structural information can be extracted from the diffraction data of increasingly poor diffraction data must be addressed. Structural problems which have the complexity of more than one molecule in the asymmetric unit present new challenges to powder X-ray diffraction [5], and recent developments in the structure solution of complicated structures using powder diffraction techniques will be highlighted [6].…”

The structure of the agrochemical fungicidal 4-chloro-3-(3,5-dichlorophenyl)-1H-pyrazole (RPA 406194) and related compounds

“…We have not solved the structure using the Rietveld refinement procedure, 18 but we have instead used the following approach, based on the CERIUS2 package. 19 (i) Building of a starting structure for 1a.…”