Question

How do you name coordination compounds?

Answer 1

Hint: The compounds containing coordination bonds are called coordination compounds. Here, the central metal ion is surrounded by a group of atoms or ions known as ligands. Three types of ligands are neutral ligands, cationic ligands, and anionic ligands. Depending on the nature of the ligand present in the coordination compounds naming of compounds also changes.

Complete step by step answer:
The rules used while naming the coordination compounds are as follows:

1. In the case of the complex ion, name the ligand first and then the metal ion.
2. When multiple ligands are present then the first name the neutral ligands, then negative ligands, and at last positive ligands.
If all ligands are of the same nature then name them as per the alphabetical order.
3. if multiple ligands are present then use prefixes like mono, bi, tri, etc for 1, 2, and 3 monodentate ligands respectively. While in the case of the polydentate ligands prefixes like bis, tris, tetrakis are used instead of bi, tri, and tetra.
4. In the case of the anionic ligand which ends with –ate replaced it with –ato and –ide with –ido.
5. Neutral ligands are named as their usual names. But some exceptions are there for example $ - {\text{NO}}$ called nitrosyl, $ - {\text{CO}}$ called carbonyl,${\text{N}}{{\text{H}}_{\text{3}}}$ named as ammine, ${{\text{H}}_2}{\text{O}}$ named as aquo, etc.
6. After naming all ligands, name the central atom or ion. If it is cation then no need to change the ion name but in the case of the anion end it with the suffix –ate.
7. If the central atom or ion is transition metal then mention its oxidation state in roman number while naming the compound.
8. End the name of the ionic species with the word ion.

For example:
1) $\left[ {{\text{Pt}}{{\left( {{\text{N}}{{\text{H}}_{\text{3}}}} \right)}_{\text{6}}}} \right]{\text{C}}{{\text{l}}_{\text{4}}}$
Here, the coordination entity ${\left[ {{\text{Pt}}{{\left( {{\text{N}}{{\text{H}}_{\text{3}}}} \right)}_{\text{6}}}} \right]^{4 + }}$ is positively charged hence name it first and then the negatively charged species.
Here, the oxidation number of the platinum is +4 and six ammonia ligands are present.
Hence, the name of the compound is hexammine platinum(IV) chloride.

2) ${\left[ {{\text{NiC}}{{\text{l}}_{\text{4}}}} \right]^{2 - }}$
Here, the coordination entity ${\left[ {{\text{Pt}}{{\left( {{\text{N}}{{\text{H}}_{\text{3}}}} \right)}_{\text{6}}}} \right]^{4 + }}$ is negative.
Here, the oxidation number of the nickel is +2 and four chloride ligands are present.
Hence, the name of the compound is tetrachloronickelate(II) ion.

Note: Coordination compounds play an important role at the industrial level because it serves as an important catalyst in various industrial processes. Also, coordination compounds are used in various biological processes. It also plays an important role in pharmaceuticals. Cis-platin is one of the important coordination compounds of platinum that plays a vital role in the treatment of cancer. In this way coordination compounds are widely used.