Throughout the whole potential ranges where underpotential deposition (upd) proceeds, the stretching absorption bands of both sulfate and phosphate anions (Vs-O and Vp-O) do not change at all with regard to band-center position. Sulfate and phosphate anions are combined with copper or zinc ions to form surface metal complexes on a Au(1 1 1) electrode surface, respectively: transition metal-oxianion (sulfate and phosphate) pseudo-complexes are formed in the course of upd processes. The surface structure of the Au(1 1 1) electrode in the topmost layer is the same as the bulk structure (I x 1), and lifting of surface reconstruction takes place in the case of Cu-upd where Cu(I)(2)SO4 and Cu(I)(3)SO4 pseudo-complexes extend on the surface, while surface reconstruction of a Au(1 1 1) electrode continues to occur in the case of Zn-upd where the Zn(I)(2)PO4 or Zn(I)(3)PO4 pseudo-complex locates. (C) 2003 Elsevier B.V. All rights reserved.