Recent experimental advancements have enabled more accurate and in-depth analysis of these materials during and after formation. The review article examines two decades of research on the non-classical formation pathways of soft and organic crystalline materials. It details the current theoretical understanding of how these materials form through non-classical pathways, including distinguishing the processes of nucleation and growth across models.
Advances in experimental methods, including in-line scattering/spectroscopy detection, cryo microscopy, and in situ liquid-phase characterization, and their application to studying soft and organic crystalline materials are also discussed.
These experimental techniques have provided strong evidence for non-classical crystallization pathways, leading to key breakthroughs in understanding these processes. However, the sole presence of a specific final product or intermediate does not prove that a material formed via a specific pathway.