Coordination compounds (complexes), also known as complexes, complex salts and complexes, contain complex molecules or ions formed by the combination of central atoms or ions with several ligand molecules or ions through coordination bonds, and are usually called "coordination units". All compounds containing coordination units are called coordination compounds. The branch of chemistry that studies complexes is called coordination chemistry. Extended information

Naming method of complexes:

(1) The key to the naming of complexes is the naming of the inner boundary of complexes (i.e. coordination ions)

The naming method of coordination ions located at the inner boundary of complexes is generally in the following order: from right to left, the number of ligands-the names of ligands [different ligand names are separated by a middle dot ()]-the combination-the center.

the valence of the central ion is calculated from the external ion charge/ligand charge according to the zero charge of the complex, and the central ion is indicated by parentheses and Roman numerals.

(2) Complexes can be regarded as salts. If the inner boundary is cation, the outer boundary must be anion; If the inner boundary is anion, the outer boundary must be cation. It can be named according to the naming method of salt, and it can be named as a certain acid or a certain chemical from right to left.

Reference: Baidu Encyclopedia-Coordination Compounds