Koordinaatsioonühend

Koordinaatsioonühend, also known as a coordination compound or complex compound, is a chemical compound consisting of a central atom or ion, typically a metal, bonded to a surrounding array of molecules or ions called ligands. These ligands are attached to the central atom through coordinate covalent bonds, where the ligand donates a pair of electrons to form the bond. The central atom is usually an element from the transition metals.

The structure and properties of a koordinaatsioonühend are determined by the nature of the central atom and the type, number, and arrangement of the ligands. The number of ligands directly attached to the central atom is called the coordination number, which can vary but is often between 4 and 6. The spatial arrangement of the ligands around the central atom defines the complex's geometry, such as tetrahedral, square planar, or octahedral.

Koordinaatsioonühendid play significant roles in various fields. In biochemistry, they are essential for life, with examples like hemoglobin (containing iron) and chlorophyll (containing magnesium). In industrial chemistry, they are used as catalysts in many organic reactions, such as the synthesis of polymers and pharmaceuticals. They also find applications in analytical chemistry for detecting and quantifying metal ions, as well as in materials science for creating compounds with specific magnetic or optical properties. The study of these compounds is a core area of inorganic chemistry.