IUPAC Nomenclature of Coordination Compounds

The ligand ethane-1,2-diamine is a neutral bidentate ligand. Since there are three of them, the prefix 'tris' is used, and the complex is a cation, so the metal name remains Cobalt.

Potassium tetracyanidonickelate(II) consists of the potassium cation (K+) and the complex anion [Ni(CN)4]2-. To balance the charges, two potassium ions are required.

EDTA (Ethylenediaminetetraacetate) has four carboxylate groups and two amine groups that can donate electron pairs to a metal ion, making it a hexadentate ligand.

According to IUPAC nomenclature rules for coordination compounds, ligands are named alphabetically before the metal atom. The ligands are diammine (from NH3), chlorido (from Cl-), and methylammine (from CH3NH2). Alphabetical order gives ammine before chlorido, then methylammine. Thus, the name is Diamminechloridomethylammineplatinum(II).

The ligands are ammine and aqua, listed alphabetically. The metal is Chromium in the +3 oxidation state, and the complex is cationic, so it is named Chromium(III).