Single-crystal X-ray Diffraction is
a non-destructive analytical technique which provides detailed information
about the internal lattice of crystalline substances, including unit cell
dimensions, bond-lengths, bond-angles, and details of site-ordering. Directly
related is single-crystal refinement, where the data generated from the X-ray
analysis is interpreted and refined to obtain the crystal structure. The most common
experimental method of obtaining a detailed structure of a molecule, that
allows resolution of individual atoms, single crystal X-ray diffraction (SXRD)
is performed by analyzing the pattern of X-rays diffracted by an ordered array
of many identical molecules (single crystal). Many pure compounds, from small
molecules to organometallic complexes, proteins, and polymers, solidify into
crystals under the proper conditions. When solidifying into the crystalline
state, these individual molecules typically adapt one of only a few possible 3D
orientations. When a monochromatic X-ray beam is passed through a single
crystal, the radiation interacts with the electrons in the atoms, resulting in
scattering of the radiation to produce a unique image pattern. Multiple images
are recorded, with an area X-ray detector, as the crystal is rotated in the X-ray
beam. Computationally intensive analysis of a set images results in a solution
for the 3D structure of the molecule.
