Question

Write the formulas for the following coordination compound -Tetraamminediaquacobalt (III) Chloride.

Answer 1

IUPAC Nomenclature of Coordination Compounds
• The cation's name comes first, followed by the anion's name.
• The ligand or ligands' name comes before the name of the central metal atom.
• If the ligand is negative, the name usually ends in 'o', and if the ligand is neutral, it usually ends in 'unmodified.'
• The number of ligands is indicated by a Greek prefix, such as mono, di, tri, tetra, penta, hexa, and so on.
• The oxidation number of the central metal atom is indicated by a Roman numeral or a zero in parenthesis.
• The name of the metal ends in 'ate' if the complex ion is negative, such as ferrate, cuprate, nickelate, cobaltate, and so on.
• If the species contains more than one ligand, the ligands are called in alphabetical order, regardless of their number.

Formulas for Tetraamminediaquacobalt (III) Chloride

• Tetraammine means four ammine ligand is present.
• Diaqua means two ${\mathrm{H}}_2\mathrm{O}$ ligand is present.
• So, the formula for Tetraamminediaquacobalt (III) Chloride is $\left[\mathrm{Co}{\left({\mathrm{H}}_2\mathrm{O}\right)}_2{\left({\mathrm{NH}}_3\right)}_4\right]{\mathrm{Cl}}_3$.