A self-assembled monolayer (SAM) of a disulfide with a pair of bicyclo [2.2.2] octane (BCO) moieties was prepared on Au(1 1 1). The resulting SAMs were separately imaged by scanning tunneling microscopy (STM) and non-contact atomic force microscopy (NC-AFM) under ultra-high vacuum at room temperature. The images of the BCO SAM by NC-AFM were similar to those by STM, in which adsorbed molecules were hexagonally packed with the spacing of ca. 6.2 nm. (C) 2002 Elsevier Science B.V. All rights reserved.