Single crystal X-ray diffraction is the traditional method for accurate crystal structure determination. A major difficulty in X-ray crystallography is the phase problem; diffracted intensities contain amplitude information but no phases. In order to solve a structure, the phases of at least the strongest reflections must be estimated by Patterson techniques, so-called direct methods or in any other way. Once the structure has been solved (i.e. the atoms found to within about 0.2 Ångström of their correct positions), then refinement is rather straight-forward for single crystal data. Typically, single crystals diffract to about 1 Â resolution. After refinement, the atomic co-ordinates are obtained with an accuracy of about 0.01 Â for organic molecules and down to 0.001 Â for inorganic structures. One limitation of single crystal X-ray diffraction is that the crystals need to be at least about 10μm in all dimensions in order to diffract, even if the radiation source is a synchrotron.