Abstract <p>There is a lack of publications devoted to the combined influence of oxygen and bismuth impurities on the structural and physicochemical properties of nickel melts or heat-resistant alloys based on it. This study examines the state of pure nickel melts and nickel containing (0.005–0.01) bismuth and oxygen during the refining process from oxygen and bismuth impurities. The influence of these impurities on the structural and physicochemical properties was studied, evaluated according to the parameters of density and surface tension of the melts. In nickel melts with bismuth and oxygen, a compression effect and negative deviation from Raoult’s law were observed. An effect of increased surface tension of a nickel melt containing oxygen with increasing bismuth concentration was found, which corresponds to the isotherm of desorption of excess substance from the surface into the bulk.</p>