Pt(110)-Br surfaces have been characterized by cyclic voltammetry, charge displacement experiments and scanning tunneling microscopy (STM). The strong specific adsorption of bromide involves charge transfer and gives rise to very stable adlayers of bromine atoms that survive emersion and transfer to a bromide-free electrolyte. These adlayers can be characterized by ex-situ STM. Bromine coverages calculated from charge displacement experiments are in the range 0.6-0.7 Br/Pt, referred to the atomic surface density of the unreconstructed surface. From STM images, the arrangement of bromine adatoms is concluded to be a distorted compact hexagonal lattice, whose coincidence with the substrate gives rise to complex structures, with preferential alignment along the [00 (1) over bar] direction.