1. In the presence of antimony compounds in electrolyte, antimony is codeposited on the cathode, which promotes the oxidation of the copper powder. 2. Small amounts (up to 0.5–1.0 mg·eq/liter) of antimony impurity in electrolyte favor the formation of loose deposits with a strongly developed dendritic particle structure, while larger amounts exert a pronounced dispersing effect on the cathodic deposit. 3. It has been shown that small amounts of antimony (up to 0.05 mg·eq/liter) have a depolarizing influence on the discharge of copper ions, while larger concentrations exhibit a passivating effect. The change in the character of the influence exerted by the impurity is ascribed to the attainment of the solubility product of basic antimony salts and antimony hydroxide in the near-cathode layer.