key term - [Cu(NH₃)₄]²⁺

Definition

[Cu(NH₃)₄]²⁺ is a coordination complex consisting of a copper(II) ion coordinated to four ammonia (NH₃) ligands. This complex showcases the principles of coordination chemistry, particularly in how central metal ions can bond with various ligands to form stable structures. The charge of +2 indicates that the copper is in the +2 oxidation state, which is crucial for understanding its reactivity and properties.

5 Must Know Facts For Your Next Test

1. [Cu(NH₃)₄]²⁺ has a square planar geometry due to the specific arrangement of the four ammonia ligands around the copper ion.
2. Copper(II) complexes, including [Cu(NH₃)₄]²⁺, often exhibit paramagnetism due to the presence of unpaired electrons in their d-orbitals.
3. Ammonia is a neutral ligand and acts as a strong field ligand, which can stabilize lower oxidation states of transition metals.
4. [Cu(NH₃)₄]²⁺ can participate in various redox reactions, making it significant in both biological and industrial processes.
5. The formation of [Cu(NH₃)₄]²⁺ demonstrates ligand substitution reactions, where water molecules in copper solutions are replaced by ammonia ligands.

Review Questions

• What is the significance of coordination number and geometry in understanding the structure of [Cu(NH₃)₄]²⁺?
  • [Cu(NH₃)₄]²⁺ has a coordination number of 4, indicating that it is surrounded by four ammonia ligands. This arrangement results in a square planar geometry, which is important for its stability and reactivity. The geometry influences the electronic properties of the complex, affecting how it interacts with light and other chemical species.
• How does the presence of ammonia as a ligand impact the properties and stability of the [Cu(NH₃)₄]²⁺ complex?
  • Ammonia is a strong field ligand that stabilizes the +2 oxidation state of copper in [Cu(NH₃)₄]²⁺. Its ability to donate electron pairs leads to stronger bonding interactions, enhancing the stability of the complex compared to those with weaker ligands. This strong ligand field effect also affects the electronic structure, contributing to its paramagnetic behavior due to unpaired electrons.
• Evaluate the role of [Cu(NH₃)₄]²⁺ in redox chemistry and its implications in biological systems.
  • [Cu(NH₃)₄]²⁺ plays a significant role in redox reactions due to its ability to interchange between different oxidation states, primarily Cu(II) and Cu(I). This versatility makes it important in various biochemical processes, such as electron transport in respiration and photosynthesis. Understanding its redox chemistry allows for insights into copper's essential functions in living organisms and its potential applications in industrial catalysis.

Related terms

Coordination Number: The number of ligand atoms that are bonded to the central metal atom 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.

Octahedral Geometry:

A common structural arrangement for coordination complexes where six ligands surround a central atom, though [Cu(NH₃)₄]²⁺ adopts a square planar geometry.