Adsorption and formation of ordered structures of Ho atoms on Mo(1 1 2) surface are studied by LEED, work function measurement and first-principle calculations. It is found that the most favorable energetically periodic structure is (3 x 2) structure at coverage of theta = 213, in which separation of Ho atoms is very close to metallic diameter of holmium. LEED measurements and the ground state analysis have revealed that structures (4 x 1) with theta = 314 and ( 5 x 1) with theta = 415 are also favorable. There are no ordered structures at low coverages although the long-range indirect interaction between adatoms is present. (C) 2014 Elsevier B.V. All rights reserved.