Twins, disorders and other demons

摘要

Dramatic improvements in both the hardware and software used to perform X-ray crystallo- graphic studies on single crystals have led to the publication of thousands of new structures each year. These improvements have also made it possible to successfully resolve a larger percentage of structural problems such as disorder and complicated twinning. Examples are included to twins that were first thought to be disorders structures with both twinning and disorder, and four-fold twinning.