The crystal structures of two polymorphic forms of maltol, C₆H₆O₃, have been determined. The polymorphs exhibit different crystal-packing arrangements through intermolecular hydrogen bonding involving the hydroxyl H atoms. Form (1) has a near planar chain of molecules linked by hydrogen bonds while form (2) has mutually hydrogen-bonded dimers. In both polymorphic forms, there are also weaker C-HO bonds which give greater stability to the chains of form (1) and link the dimers in form (2).

The molecular structure of 6-L-alanineferrirubin tetradecahydrate, [Fe(C₄₁H₆₄N₉O₁₆)].14H₂O, has been determined in order to confirm its chemical structure. The structural results show that the presence of an alanine in place of a serine or a glycine at position 6 in the cyclic hexapeptide has very little effect on the conformation of the 18-membered ring or on the geometry of the octahedral iron coordination.

The molecular geometry of a major metabolite, C₁₄H₁₉NOS, of a potent anti-arrhythmic drug, 7-benzyl-3-thia-7-azabicyclo­[3.3.1]nonane (BRB-I-28), has been determined by X-ray diffraction. The 3,7-dihetero bicyclic system of the sulfoxide molecule adopts a chair–chair conformation like the HClO₄ salt of the BRB-I-28 molecule. The SN contact distance of 2.863 (2) Å in the present molecule is significantly shorter than that found in the crystal structure of its precursor [3.038 (4) Å]. The overall molecule possesses pseudo-mirror symmetry.