A coordination compound has formula 3 3 CoCl .4NH . it does not liberate ammonia but precipitates chloride ion as AgCl . Give the IUPAC name of the complex and write its structural formula.

To determine the IUPAC name of the coordination compound with the formula CoCl₃·4NH₃, we first need to analyze its components and structure. This compound contains cobalt (Co) as the central metal ion, chloride ions (Cl⁻) as ligands, and ammonia (NH₃) as another type of ligand. The fact that it does not liberate ammonia but precipitates chloride ions as AgCl suggests that the ammonia is coordinated to the cobalt and does not dissociate in solution.

Identifying the Coordination Complex

The coordination number of cobalt in this complex is 6, which is typical for cobalt(III) complexes. The ligands present are four ammonia molecules and three chloride ions. In coordination chemistry, ammonia is a neutral ligand, while chloride is a negatively charged ligand. The overall charge of the complex is neutral, as the cobalt is in the +3 oxidation state.

Determining the IUPAC Name

In naming coordination compounds, the ligands are named first, followed by the metal. Neutral ligands like ammonia are named as "ammine," and anionic ligands like chloride are named as "chloro." Since there are four ammonia ligands and three chloride ligands, we use the prefixes "tetra-" for four and "tri-" for three.

Putting this all together, the IUPAC name of the complex is:

Structural Formula Representation

The structural formula of the complex can be represented as follows:

• Central metal ion: Co³⁺
• Ligands: 4 NH₃ and 3 Cl⁻

In a typical octahedral arrangement, the ammonia ligands will occupy four of the six coordination sites, while the chloride ions will occupy the remaining two. The structural formula can be depicted as:

In this representation, the cobalt ion is at the center, with the ammonia and chloride ligands arranged around it. The ammonia ligands are shown as NH₃, and the chloride ions as Cl⁻, indicating their coordination to the cobalt ion.

Summary of Key Points

• The coordination compound is CoCl₃·4NH₃.
• The IUPAC name is Tetrachlorocobalt(III) ammine.
• The structure features cobalt at the center with four ammonia and three chloride ligands.

This compound exemplifies the fascinating world of coordination chemistry, where the arrangement and types of ligands can significantly influence the properties and behavior of the complex. Understanding these relationships is crucial for exploring more advanced concepts in inorganic chemistry.