Zn2

Zn2+, or the zinc(II) ion, is the divalent cation that dominates zinc chemistry in minerals and aqueous solutions. It is the most common oxidation state of zinc in nature and in biological systems. In minerals, zinc is chiefly found in ores such as sphalerite (ZnS) and zinc carbonates, which are processed to produce zinc metal and zinc compounds.

In aqueous solutions, Zn2+ forms the hexaaqua complex [Zn(H2O)6]2+. Depending on pH and ligands, it hydrolyzes to species such as [Zn(H2O)5(OH)]+ and Zn(OH)2(aq), and it readily forms complexes with chloride, sulfate, carbonate, phosphate, and organic ligands. The coordination number typically ranges from four to six, reflecting flexible binding to surrounding ligands in various chemical environments.

Zinc is an essential micronutrient for all organisms. Zn2+ acts as a structural cofactor in zinc finger proteins and as a catalytic cofactor in enzymes such as carbonic anhydrase, alkaline phosphatase, and metalloproteases. Cellular uptake is mediated by ZIP transporters, while ZnT transporters and metallothioneins support storage and efflux. Deficiency can impair growth and immune function; excess can disrupt metal homeostasis and cause toxicity in some systems.

Zn2+ finds industrial use in galvanization and in the production of zinc oxide and various zinc salts for fertilizers and electronics. In the environment, zinc mobility depends on pH and complexation; elevated levels can harm aquatic life, while precipitation as Zn(OH)2 or ZnCO3 can limit mobility.