key term - [Co(NH3)6]Cl3

Definition

[Co(NH3)6]Cl3 is a coordination compound where cobalt (Co) is the central metal ion surrounded by six ammonia (NH3) ligands, forming a complex cation. The presence of three chloride ions (Cl-) as counterions balances the charge of the complex. This compound showcases important features such as coordination number, oxidation state of the metal, and the role of ligands in the structure and behavior of coordination compounds.

5 Must Know Facts For Your Next Test

1. [Co(NH3)6]Cl3 has a coordination number of 6, indicating that six ammonia molecules are coordinated to the cobalt ion.
2. In this complex, cobalt typically exhibits an oxidation state of +3, which is common for cobalt complexes with ammonia as ligands.
3. The ammonia ligands in [Co(NH3)6]Cl3 are neutral and provide a strong field, leading to potential low-spin configurations depending on the metal's oxidation state.
4. Isomerism can occur in coordination compounds like [Co(NH3)6]Cl3, particularly geometric isomerism and optical isomerism due to its symmetrical arrangement.
5. The chloride ions present in [Co(NH3)6]Cl3 serve as counterions and do not directly coordinate with the cobalt center, affecting the solubility and overall charge balance of the compound.

Review Questions

• How does the coordination number in [Co(NH3)6]Cl3 affect its structure and stability?
  • The coordination number of 6 in [Co(NH3)6]Cl3 indicates that six ammonia molecules surround the cobalt ion, creating an octahedral geometry. This specific arrangement leads to significant stability due to effective overlap between the ligand's orbitals and the d-orbitals of cobalt. The octahedral structure also influences the electronic properties of the complex, making it more stable compared to complexes with lower coordination numbers.
• Discuss how isomerism can manifest in complexes like [Co(NH3)6]Cl3 and its implications for chemical behavior.
  • In [Co(NH3)6]Cl3, geometric isomerism can occur, resulting in different spatial arrangements of ligands around the cobalt center. For example, it can exist as cis or trans isomers depending on how ligands are arranged relative to each other. This isomerism affects physical properties like boiling point and solubility, as well as reactivity towards other chemical species, demonstrating how structural variations can lead to differing chemical behaviors within similar coordination compounds.
• Evaluate how understanding the oxidation state of cobalt in [Co(NH3)6]Cl3 contributes to predicting its reactivity and interaction with other ligands.
  • Knowing that cobalt typically has an oxidation state of +3 in [Co(NH3)6]Cl3 allows chemists to predict its reactivity patterns with potential ligands. Higher oxidation states generally make the metal more electrophilic, which increases its ability to interact with electron-rich species. As a result, this knowledge helps in designing new complexes or reactions by choosing appropriate ligands based on their donation abilities and steric effects relative to the established oxidation state of cobalt.

Related terms

Coordination Number:

The number of ligand atoms that are bonded to a central metal ion in a coordination complex.

Ligand:

A molecule or ion that donates a pair of electrons to a central metal atom to form a coordination complex.

Oxidation State:

The charge of a metal ion in a compound, which reflects its electron loss or gain during bonding.