When propionic acid is heated with mercuric propionate the condensation polymer of the alpha-monomercurated propionic acid is obtained along with traces of the dimercurated acid. When n-butyric acid is heated with mercuric n-butyrate the condensation polymer of the alpha-monomercurated n-butyric acid is obtained together with about a 20% yield of the dimercurated one. In contrast, n-valeric and isovaleric acids are mainly dimercurated. The site of mercuration, established by H-1 and C-13 NMR spectroscopy, was confirmed by an X-ray crystal structure analysis of the 2,2-bipyridyl complex of 2-(nitratomercurio)propionic acid. The NMR spectra showed a number of long range Hg-199-H-1 (up to five bonds) and Hg-199-C-13 (up to four bonds) spin-spin couplings and the relation of three-bond Hg-199-C-13 couplings to molecular conformation. In the crystal structure of [CH3CH(Hg(C10H8N2))COOH]NO3 mercury is bonded to the alpha-carbon atom of the propionic acid at a distance of 2.11(1) angstrom and to the nitrogen atoms of the bipyridyl ligand at 2.226(9) and 2.423(7) angstrom.