Publisher Summary This chapter reviews the structural implications of the vibrational spectroscopic results from the adsorption of ethene and the higher alkenes on different metal surfaces. Alkenes are chosen because the spectra of their adsorbed species have been investigated in most detail. The emphasis has been on an exploration of the structures of the temperature-dependent chemisorbed species on different metal surfaces. The emphasis has been on an exploration of the structures of the temperature-dependent chemisorbed species on different metal surfaces. Particular attention has been directed to the spectra obtained on finely divided (oxide-supported) metal catalysts. The chapter also presents reviews of the fewer spectra from other families of adsorbed hydrocarbons, i.e., the alkynes, the alkanes (acyclic and cyclic), and aromatic hydrocarbons. Knowledge of the chemisorbed species present on a surface provides an essential database for the investigation of catalytic and other reaction mechanisms in which they are involved. The elucidation of reaction mechanisms in turn requires studies of chemical kinetics. An increasing number of such kinetic studies are now being made which involve vibrational spectroscopy and hydrocarbon adsorbates.