The adsorption and reactions of cis-1,2-dichloroethene on Cu(110) have been investigated using Reflection Absorption Infrared Spectroscopy, Temperature Programmed Desorption and Molecular Beam Adsorption Reaction Spectroscopy, and the behaviour compared with that of the previously studied IS. Haq, S.C. Laroze, C. Mitchell, N. Winterton, R. Raval, Surf. SCi. 531 (2003) 1451 trans isomer. No isomerisation between the cis and trans isomers was seen. The data reveal that, although the related positions of the Cl atoms force different adsorption geometries for the two isomers, the behaviour of both compounds follows a very similar general reaction pathway which is critically temperature-dependent and can be described in terms of three main regimes: Regime I Occurring at low temperatures in which intact molecular adsorption Occurs; Regime II, extending over the temperature range of 155-280 K, in which desorption/dechlorination events are triggered: and, finally, Regime III, over 280-450 K, is governed, for both isomers, by the behaviour of the acetylene intermediate at the Surface which trimerises to form benzene and desorbs above 350 K. (c) 2009 Elsevier B.V. All rights reserved.