Evidence for pseudo bridge bonding of c(2×2)-O on Ni(100)

New low-energy electron-diffraction intensity measurements and dynamical calculations indicate that oxygen in a c(2×2) overlayer resides 0.800.025 above the top layer of Ni atoms and is displaced 0.300.1 from the fourfold hollow position along a 110 direction. This produces a structure having C2V symmetry with two inequivalent nearest-neighbor Ni-O bond distances of 1.750.05 and 2.140.08. © 1983 The American Physical Society.