The adsorption process of irreversibly adsorbed Sb on Au(1 1 1) at open circuit potential (similar to0.2 V) was investigated with in situ STM. The adlayer of oxygenated Sb nucleated and grew on terraces and at step edges. The oxygenated Sb domains on terraces were round-shaped islands, whose size ranged from 3 to 6 nm in diameter. The adlayers originating from step edges, on the other hand, grew perpendicularly to the steps to show terrace-like uniform domains. There was no island of Sb on such terrace-like oxygenated domains. In the long term, the island-shaped domains and the terrace-shaped domains were inter-connected to produce a networked monolayer of oxygenated Sb. The network adlayer of oxygenated Sb was modified to a simple layer of nano-islands of elemental Sb, when the electrode potential was held at -0.25 V. Upon a Subsequent re-oxidation, the Sb-covered Au(1 1 1) surface showed a complex morphology, filled with many pits and relatively wide islands. Also, atomic images of the Sb layers on Au(1 1 1) at various potentials were presented as well. (C) 2003 Elsevier B.V. All rights reserved.