oxiânions
Oxiânions are polyatomic anions that contain oxygen as the central atom or as a primary component. These species are characterized by a negative charge and are formed by one or more oxygen atoms bonded to another atom, often a nonmetal, in a molecular structure. The most common elements forming oxiânions with oxygen include sulfur, phosphorus, nitrogen, carbon, and silicon.
Examples of prominent oxiânions include the sulfate ion (SO4^2-), the phosphate ion (PO4^3-), the nitrate ion (NO3^-),
Oxiânions are fundamental building blocks in mineralogy, forming the basis of many silicate and carbonate minerals