Kompleksselt

Kompleksselt is a type of salt in coordination chemistry in which one of the ions that constitutes the salt is a coordination complex. The complex can be a cation or an anion and is formed when a central metal ion is coordinated by surrounding ligands such as ammonia, water, cyanide, or ethylenediamine. The overall compound is electrically neutral, with the charged complex balanced by counterions.

In a complex salt, the complex portion contributes most of the chemical identity and often determines properties such as color, solubility, and reactivity. Common examples include salts that contain a complex anion or a complex cation. For instance, potassium ferrocyanide, K4[Fe(CN)6], and potassium ferricyanide, K3[Fe(CN)6], feature the [Fe(CN)6]4– and [Fe(CN)6]3– complex anions, respectively, balanced by potassium ions. Another well-known example is hexamminecobalt(III) chloride, [Co(NH3)6]Cl3, where a cationic cobalt complex is paired with chloride counterions. A further example is diamminesilver(I) nitrate, [Ag(NH3)2]NO3, which consists of a complex cation and a nitrate counterion.

Preparation and applications vary but often involve forming the coordination complex first, then combining it with suitable counterions to yield a crystalline salt. Such salts are studied in inorganic synthesis, crystallography, and analytical chemistry and illustrate how ligand chemistry modulates the properties of solid-state materials.

See also: coordination chemistry, complex ion, ligand, chelation, salt.