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Term symbol of a d7 complex
Accepted Answer
The term symbol of a d7 complex depends on the spin state and the number of unpaired electrons. Here's how to determine it:
1. Identify the spin state:
- High spin: All electrons are placed in separate orbitals before pairing in the same orbital (Hund's rule). This results in more unpaired electrons.
- Low spin: Electrons pair up in orbitals before occupying empty orbitals.
2. Count the unpaired electrons:
- High spin: In a d7 configuration, high spin will have 3 unpaired electrons.
- Low spin: In a d7 configuration, low spin will have 1 unpaired electron.
3. Determine the term symbol:
- The term symbol is represented as 2S+1LJ where:
- S is the total spin angular momentum (multiplicity). It is calculated as S = (1/2)
n, where n is the number of unpaired electrons.
- L is the total orbital angular momentum. For d orbitals, L = 2, so L = 2 is assigned the letter D.
- J is the total angular momentum, J = L + S.
Examples:
- High spin d7 complex:
- S = (1/2)
3 = 3/2
- 2S+1 = 2(3/2)+1 = 4
- L = 2 (D)
- J = 2 + 3/2 = 7/2
- Term symbol: 4D7/2
- Low spin d7 complex:
- S = (1/2)
1 = 1/2
- 2S+1 = 2(1/2)+1 = 2
- L = 2 (D)
- J = 2 + 1/2 = 5/2
- Term symbol: 2D5/2
Note: The actual term symbol may vary depending on the specific ligand field strength and the metal ion involved.
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