[Co(NH3)6]3+

Definition

[Co(NH3)6]3+ is a coordination complex consisting of a central cobalt(III) ion surrounded by six ammonia ligands. It is an important example of coordination chemistry in transition metals, where the metal ion forms stable bonds with multiple ligands to create a complex ion.

5 Must Know Facts For Your Next Test

1. The cobalt(III) ion in [Co(NH3)6]3+ has an oxidation state of +3, meaning it has lost three electrons from its neutral state.
2. The six ammonia (NH3) ligands are arranged in an octahedral geometry around the central cobalt(III) ion.
3. Coordination complexes like [Co(NH3)6]3+ are important in biological systems, where they play roles in enzyme catalysis and electron transfer processes.
4. The strong field ligands (such as ammonia) in [Co(NH3)6]3+ lead to a high-spin configuration of the cobalt(III) ion, with all three unpaired electrons.
5. Complexes like [Co(NH3)6]3+ can exhibit different colors due to the absorption of specific wavelengths of light by the d-orbital electrons of the metal ion.

Review Questions

• Explain the structure and bonding in the [Co(NH3)6]3+ coordination complex.
  • The [Co(NH3)6]3+ coordination complex consists of a central cobalt(III) ion with an oxidation state of +3, surrounded by six ammonia (NH3) ligands arranged in an octahedral geometry. The cobalt ion forms coordinate covalent bonds with the nitrogen atoms of the ammonia ligands, creating a stable complex ion. The strong field ligands (ammonia) lead to a high-spin configuration of the cobalt(III) ion, with all three of its d-orbital electrons unpaired.
• Describe the role of coordination complexes like [Co(NH3)6]3+ in biological systems.
  • Coordination complexes, including [Co(NH3)6]3+, play important roles in biological systems. They can be involved in enzyme catalysis, where the metal ion acts as a cofactor, facilitating chemical reactions. Coordination complexes also participate in electron transfer processes, such as those found in the electron transport chain of cellular respiration. Additionally, the unique properties of coordination complexes, such as their color and reactivity, can be utilized in biological applications, like the use of vitamin B12 (which contains a cobalt ion) as a dietary supplement.
• Analyze how the properties of the [Co(NH3)6]3+ complex, such as its geometry and electronic configuration, influence its behavior and applications.
  • The octahedral geometry and high-spin configuration of the [Co(NH3)6]3+ complex are key to its properties and applications. The six ammonia ligands arranged around the cobalt(III) ion in an octahedral arrangement provide stability to the complex and influence its reactivity. The strong field ligands (ammonia) lead to a high-spin configuration of the cobalt(III) ion, with all three d-orbital electrons unpaired. This electronic configuration affects the complex's color, magnetic properties, and potential for redox reactions, making it useful in various applications, such as in pigments, catalysts, and as a model system for understanding transition metal chemistry.

Related terms

Coordination Complex: A coordination complex is a central metal ion bonded to surrounding ligands, forming a stable chemical entity.

Ligand:

A ligand is an atom, ion, or molecule that forms a coordinate covalent bond to a central metal ion in a coordination complex.

Oxidation State:

The oxidation state of an atom is a measure of the degree of oxidation of an atom in a chemical compound, and is represented by a number that is equal to the charge of the atom.