AbstractNucleation of LiKSO4(LKS) crystals from non‐equimolar solutions may occur epitaxially on the surface of previously nucleated β‐K2SO4(KS) crystals. Both compounds evince a profound hexagonal substructure, and have common topological features and similar coordination schemes. Moreover, they may be related by quantitative similarities between their translation parameters and by correspondence between their bond chains along the directions of epitaxy. The planes of epitaxy are (001)KS, and (0001)LKS' and on these planes [010]KSis always parallel to [010]LKS' with a misfit of 12.19%. Another pair of directions, [110]KSand [100]LKS'showing a small angular misfit (0.18°), exhibit an even lower linear misfit (3