Adsorption of CS2 as well as of mixtures of CS2 and O-2 of varying compositions on a clean Ni(110) surface has been investigated using X-ray photoelectron spectroscopy. Pure CS2 adsorbs dissociatively giving rise to graphitic carbon (Cls, 285 eV), chemisorbed sulfur (S2p, 164 eV) and perhaps a small proportion of CS(a) (Cls, 286 eV). A CS2-O-2 mixture dilute in oxygen (220:1) gives rise to COS(a) (O1s, 534 eV) due to the reaction between the O1-(s) and CS(s) transients. The COS(a) species is also formed in the case of a 15:1 CS2-O-2 mixture, the other prominent surface species being O1-(a) (531 eV). When a mixture containing comparable proportions Of CS2 and 02 (2:1) is dosed, mainly O2- (oxidic) species (0 Is, 530 eV) is formed with no evidence for sulfur on the surface. When O-2 and CS2 are dosed in a sequential manner, there is some formation of COS(a). On the other hand, when O-2 is dosed on a surface predosed with CS2, adsorption of oxygen is inhibited. (C) 2002 Elsevier Science B.V. All rights reserved.