Modern X-ray Diffraction Methods in Mineralogy and Geosciences

Abstract

A century has passed since the first X-ray diffraction experiment (Friedrich et al. 1912). During this time, X-ray diffraction has become a commonly used technique for the identification and characterization of materials and the field has seen continuous development. Advances in the theory of diffraction, in the generation of X-rays, in techniques and data analysis tools changed the ways X-ray diffraction is performed, the quality of the data analysis, and expanded the range of samples and problems that can be addressed. X-ray diffraction was first applied exclusively to crystalline structures idealized as perfect, rigid, space and time averaged arrangements of atoms, but now has been extended to virtually any material scattering X-rays. Materials of interest in geoscience vary greatly in size from giant crystals (meters in size) to nanoparticles (Hochella et al. 2008; Waychunas 2009), from nearly pure and perfect to heavily substituted and poorly ordered. As a consequence, a diverse range of modern diffraction capabilities is required to properly address the problems posed. The time and space resolution of X-ray diffraction now reaches to nanoseconds and tens of nanometers. Time resolved studies are used to unravel the mechanism and kinetics of mineral formation and transformations. Non-ambient conditions such as extreme pressure and temperature are created in the laboratory to investigate the structure and properties of the Earth’s deep interior and the processes that shape the planet. This chapter is not intended to be comprehensive or detailed, because diffraction is such a vast subject. We will, however, summarize the principles of diffraction theory under the assumption that the reader is familiar with basic concepts of the crystalline state. We will briefly review the basics of diffraction techniques, using laboratory and synchrotron X-ray sources and highlight some of their applications in geoscience. For briefness, we will omit the discussion of …