The atomic structure of the Ni(110)4 x 1-S reconstruction has been determined on the basis of surface X-ray diffraction measurements. An analysis of the in-plane diffraction data shows that the model consists of Ni rows along the  direction, two for every 4 x 1 unit cell, corresponding to 0.5 ML Ni coverage. The S is chemisorbed in pseudo two-fold hollow sites both on the Ni rows and in the troughs between the rows with a S coverage of 0.75 ML. Furthermore, rod-scans along fractional-order reflections reveal sub-surface relaxations. The results are in good agreement with recent STM and previous AES and radioactive tracer studies.
Foss, M., Feidenhans'l, R., Nielsen, M., Findeisen, E., Buslaps, T., Johnson, R. L., Besenbacher, F., & Stensgaard, I. (1993). X-ray diffraction investigation of the sulphur induced 4x1 reconstruction of Ni(110). Surface Science, 296, 283-290. https://doi.org/10.1016/0039-6028(93)90024-E