The advent of flotation, with selective interaction of reagents with minerals at its core, has greatly advanced the development of modern mining. Ever since, there has been continuous researched into the mechanism of mineral-reagent interactions, in an effort to design and develop more effective reagents. A unique perspective from coordination is presented to illustrate the principles of reagent molecules interacting with metal ions on mineral surface. For the first time, the influence is unveiled of mineral crystal structures and surrounding atoms on metal ion properties and further on mineral-reagent interactions. The introduction of classical theories for modern chemistry, including orbital structure, electron spin and orbital symmetry matching, into flotation is realized. Researchers, engineers and graduate students among others in the field of mineral processing may gain new insight into flotation and the development of novel reagents.