4coordination

4coordination refers to a type of chemical coordination complex where a central atom or ion is bonded to four surrounding ligands. The number four indicates the coordination number, which is the count of sigma bonds between the central atom and the ligands. The geometry of these complexes can vary significantly, with the most common arrangements being tetrahedral and square planar. In a tetrahedral complex, the four ligands are positioned at the vertices of a tetrahedron around the central atom. In contrast, a square planar complex features the four ligands arranged in a square around the central atom, lying in the same plane. The specific geometry adopted by a 4-coordinate complex depends on factors such as the electronic configuration of the central atom, the nature of the ligands, and steric considerations. These complexes are prevalent in various fields of chemistry, including inorganic chemistry, organometallic chemistry, and biochemistry, where they play roles in catalysis, color, and biological processes. Examples include [Cu(NH3)4]2+ (tetrahedral) and [PtCl4]2- (square planar).