  Many ordered adlayer structures have been reported for CO on the (100)
surfaces of Pt, Rh, Pd, Ni and Cu. Also, some ordered structures are known for
NO on the same surfaces. The current review includes all those articles that
give a graphical representation of the position of the adsorbates inside the
unit cell. The emphasis is on the case of CO on Pt(100) and Rh(100), but also
structures are included for adsorption on the (100) surface of other transition
metals, as well as references for the case of NO adsorption.
