High-Spin Complex

Definition

A high-spin complex is a type of coordination complex in which the transition metal center has the maximum number of unpaired electrons, resulting in a high total spin quantum number. This occurs when the energy difference between the t2g and eg orbitals is relatively small, allowing the electrons to occupy the available orbitals with parallel spins.

5 Must Know Facts For Your Next Test

1. In a high-spin complex, the energy difference between the t2g and eg orbitals is relatively small, allowing the electrons to occupy the available orbitals with parallel spins.
2. High-spin complexes typically have a larger number of unpaired electrons compared to low-spin complexes, which have a greater energy difference between the t2g and eg orbitals.
3. The spin multiplicity of a high-spin complex is determined by the number of unpaired electrons, and is given by the formula 2S + 1, where S is the total spin quantum number.
4. High-spin complexes are often observed in transition metal complexes with weak-field ligands, such as chloride, bromide, or thiocyanate ions.
5. The magnetic properties of high-spin complexes, such as their magnetic susceptibility and magnetic moment, are influenced by the number of unpaired electrons and the spin multiplicity.

Review Questions

• Explain the relationship between the energy difference of the t2g and eg orbitals and the spin configuration in a high-spin complex.
  • In a high-spin complex, the energy difference between the t2g and eg orbitals is relatively small. This allows the electrons to occupy the available orbitals with parallel spins, resulting in the maximum number of unpaired electrons. The smaller the energy gap between the t2g and eg orbitals, the more favorable it is for the electrons to occupy the orbitals with parallel spins, leading to the formation of a high-spin complex.
• Describe how the spin multiplicity of a high-spin complex is determined and how it relates to the number of unpaired electrons.
  • The spin multiplicity of a high-spin complex is determined by the number of unpaired electrons. The formula to calculate the spin multiplicity is 2S + 1, where S is the total spin quantum number. The total spin quantum number is the sum of the individual spin quantum numbers of the unpaired electrons. In a high-spin complex, the number of unpaired electrons is maximized, leading to a higher spin multiplicity compared to a low-spin complex, which has a smaller number of unpaired electrons.
• Analyze the factors that influence the formation of high-spin complexes and discuss their implications on the magnetic properties of the complex.
  • The formation of high-spin complexes is favored when the energy difference between the t2g and eg orbitals is relatively small, as this allows the electrons to occupy the available orbitals with parallel spins. This is often observed in transition metal complexes with weak-field ligands, such as chloride, bromide, or thiocyanate ions. The high number of unpaired electrons in a high-spin complex results in a higher spin multiplicity, which directly affects the magnetic properties of the complex. These magnetic properties, including magnetic susceptibility and magnetic moment, are crucial in understanding the behavior and applications of high-spin coordination complexes.

Related terms

Coordination Complex: A coordination complex is a structure consisting of a central metal atom or ion bonded to a number of surrounding ligands.

Spin Quantum Number:

The spin quantum number is a measure of the intrinsic angular momentum of an electron, which can have a value of either +1/2 or -1/2.

Crystal Field Theory:

Crystal field theory is a model used to explain the electronic structure and properties of coordination complexes, based on the interaction between the metal ion and the surrounding ligands.