The (0001) plane of a cleaved zinc single crystal was oxidized in a controlled way under a low pressure oxygen ambient at 100 degrees C. Low Energy ion Scattering (LEIS) (500 eV He+) was used to investigate the short range. atomic structure of this surface by studying the anisotropy in the scattered Zn and O intensities caused by shadowing phenomena. These shadowing effects were also characterised on both (0001) and (000 (1) over bar) polar surfaces of single-crystalline zinc oxide, which features the non-centrosymmetric Wurtzite structure. Direct comparison of the results for the oxidized zinc metal surface with those of the polar surfaces of zinc oxide as references, unambiguously proves that, in the early stages of the oxidation, the structure of Zn(0001)+O corresponds to that of ZnO(0001), the Zn termination of ZnO. It thus appears that, somewhat unexpectedly, the O-atoms are situated in a subsurface position. (C) 1997 Elsevier Science Ltd. All rights reserved.