The atomic-scale structure of Zn 2 + incorporated at the CaCO 3 (1014) surface by adsorption from solution was determined by X-ray standing wave triangulation and surface extended X-ray absorption fine structure spectroscopy. At low coverage (approximately 0.1ML), Zn 2 + substitutes for Ca 2 + in the surface layer. Structural relaxation of the adjacent in-plane CO 2 - 3 ions in the host surface is shown by the reduced nearest-neighbor distance of Zn-O relative to Ca-O. Relaxation of the Zn 2 + ion in the out-of-plane direction is shown by the displacement of its lattice position from the ideal Ca 2 + position. These relaxations, resulting in a local lattice buckling feature at the Zn 2 + adsorption site, can be fully explained as the combined effect of the electrostatic relaxation of the nearest-neighbor anions in response to the smaller size of Zn 2 + , and the bonding asymmetry due to surface truncation.