There is now a matter of cadmium acetate and manganese iodide (II) co-sinking. In the past, there were people who worked in the chemical process, and wanted to obtain the precipitation of the two. It is to take the liquid of cadmium acetate and the liquid of manganese iodide (II), and put them in one place. When the two are mixed, a subtle change occurs in the liquid. The ions intersect and interact, and gradually the particles gather into clusters. Soon, the precipitation gradually emerges and sinks at the bottom of the vessel. The nature of this precipitation is both cadmium and manganese, and the color state is specific. Workers observe the changes in detail and record the details, in order to study the characteristics of this precipitation in various situations, so as to prepare for other days, for the progress of chemical affairs, or to be beneficial.