TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The In source comprises In-chloride, In-sulfate, In-acetate, In-carbonate, In-nitrate, In-perchlorate, In-phosphate, In-oxide or In-hydroxide. The solvent comprises water. The surface of the conductor comprises copper or gallium.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The weak acid is citric acid. The conjugate salt can be sodium citrate, lithium citrate, potassium citrate, and/or organically modified citrate. The organically modified citrate comprises citrate moiety including organic groups, which replaces hydrogen atoms that are directly connected to a carbon or oxygen bonded to carbon 2 of the citrate moiety, or hydroxyl group bonded to carbon 2 of the citrate moiety. The electroplating solution comprises no organic additives. Preferred Parameters: The electroplating solution has pH value of below 3.5, preferably below 2.5. The In ions have concentration of greater than or equal to 0.1 M. Preferred Method: The method further comprises controlling the temperature of the solution at 10-60 degrees C before the step of electrodeposition. EXAMPLE - Aqueous plating solution containing 0.1-0.3 M indium chloride, 0.2-0.5 M sodium citrate, and 0.1-0.3 M citric acid was prepared. The pH value of the solution was adjusted to 1.5-3.5. Indium was electrodeposited on the copper surfaces. Highly adherent indium films with surface roughness of less than 10 nm were obtained for a thickness of 200-400 nm. The plating efficiency was measured and found to be 95-100%. The resultant indium film was shiny, silvery white, smooth and defect-free. Indium was also plated on other metal surfaces using the citrate indium plating baths with high- plating efficiency. The indium citrate solution contained 0.2 M indium chloride, 0.15 M citric acid and 0.35 M sodium citrate. The plating process produced uniform, smooth and defect free indium films demonstrating the suitability of the solution to large scale manufacturing.