University of Bristol scientists have developed a soap, composed of iron rich salts, that responds to a magnetic field when placed in solution. Scientists have been searching for a way to control soaps when they are within a solution to increase their ability to dissolve oils in water and then remove them. It had been assumed that their metallic centers were too isolated, preventing the long-range interactions required for magnetic activity. This soap was created by dissolving iron in a mixture composed of chloride and bromide ions. The potential applications for these soaps are huge. Their reaction to external stimuli, such as their electrical conductivity, melting point, the shape of aggregates and how its dissolves, allows it to be altered by a magnetic switch. These factors, which are key in the effectiveness of soaps in a variety of industrial settings, could previously only be controlled by adding an electric charge or changing the pH, temperature or pressure of the system.