Evolution of diffraction methods for solving crystal structures

The practices for determining the atomic structures in crystals have changed greatly over the century since Lawrence Bragg introduced the trial-and-error method by which he solved structures for rocksalt, iron pyrite and other salts and minerals. Structure determinations for biological macromolecules first borrowed from the small-molecule tradition that evolved, notably adopting isomorphous replacement; subsequently, however, new approaches have grown to dominate, notably anomalous diffraction and molecular replacement.