ABSTRACT
The X-ray diffraction technique has been responsible for important fundamental and structural results in varied areas of solid-state science, such as solid-state physics and chemistry, mineralogy, and materials science. It is the most general experimental method for the determination of the structure of molecular and ionic compounds. With single-crystal diffraction data, the method has reached a remarkable degree of development and, combined with integrated software, it is widely used routinely in X-ray diffraction laboratories. Although the powder method has been employed in many applications (e.g. , phase identification, determination of precise unit cell parameters and structure imperfections) since its introduction in 1916, it is only in the late 1980s that the determination of unknown crystal structures from powder data emerged as a powerful tool to investigate the structure of materials obtained only in a powder form. This remarkable transformation of the powder method has been the consequence of a new methodology developed from the late 1960s and the introduction of a new instrumentation with higher resolution.
