oxysalt

An oxysalt is a salt that contains an oxoanionic polyatomic ion, i.e., an anion built from an oxoacid by replacing hydrogen with a metal cation or another counterion. In practice, oxysalts are salts of metal cations with oxoanions such as sulfate (SO4^2−), nitrate (NO3^−), carbonate (CO3^2−), phosphate (PO4^3−), chromate (CrO4^2−), dichromate (Cr2O7^2−), perchlorate (ClO4^−), and silicate (SiO3^2−). These compounds are primarily ionic and crystallize in well-defined lattices; their properties, especially solubility and melting points, depend on the specific cation–anion combination.

Formation: oxysalts are typically formed by neutralization of an oxoacid with a base, by metathesis between salts, or by precipitation from solution. They can also arise when a cation from one salt binds to an oxoanionic fragment from another source.

Applications: oxysalts are ubiquitous in chemistry and industry. Nitrates and nitrites are important as fertilizers and oxidizers; sulfates serve in construction materials and as pigments; phosphates are central to agriculture and corrosion control; carbonates feature in baking, water treatment, and glassmaking.

Nomenclature: the label oxysalt appears in older or more systematic inorganic literature to designate salts of oxoanions derived from oxoacids. In many modern contexts, chemists refer to these species simply as salts of oxoanions, with specific names for each anion.