1995 年 37 巻 2 号 p. 128-133
A new concept of “the formation of quasi-compounds and their self-ordering on metal surfaces” is reviewed. When Cu (110), Ag (110), Ni (110) are exposed to O2 at room temperature, one dimensional quasi-compounds of metal-oxygen chains are grown on the surfaces in the  direction. The P (n×1) structure of the Ag-O chanins on Ag (110) surface is rationalized by a specific self-ordering of Ag-O quasi-compound on Ag (110) surface. Based on the idea of quasi-compound formation, a new Ag (110) surface on which Cu-O chains are grown in the  was prepared. On the other hand, H2 on Ni (110) surface undergoes the growth of one dimentional Ni-H strings in the  direction at room temperature. Coadsorption of H2 on a p (3×1) Ni-O/Ni (110) surface makes compress the p (3×1) Ni-O to the p (2×1) arrangement. These atom scale phenomena can not be explained by the traditional concept of the adsorption or coadsorption, but can be rationalized by the concept of the quasi-compounds proposed in this review. The concept of the qusi-compounds is inevitable to understand the alloy and/or bimetallic surfaces. For example, prominent catalysis of the Pt-Rh (100) alloy and Pt/Rh (100) and Rh/Pt (100) bimetallic surfaces for the NOx reduction is explained by the formation of a Rh-O pverlayer on a Pt enriched 2nd layer.