Watching solids crystallise using in situ powder diffraction

The study of the chemical processes that occur during the synthesis of inorganic solids has attracted much recent attention. The ultimate aim of these experiments is the atomic level understanding of reaction mechanisms which lead to the formation of extended inorganic solids, so that rational design of new materials can be achieved. Solid-state syntheses are typically performed under non-ambient temperature and pressures in sealed containers so specialised apparatus must be constructed to allow us to directly probe these reaction mixtures. We review the use of in situ powder diffraction to investigate the formation of crystalline solids in real time, and discuss the latest developments in the technology required for these challenging experiments