Aluminum hexamethyl (Al2(CH3)6) forms a dimeric structure featuring two ( 3-center 2-electron) or (3c-2e) banana bonds and twenty-two ( 2-center 2-electron) (2c-2e) bonds.
Structure Overview
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- Dimer Formation: Two units of Al(CH3)3 link together through two bridging methyl groups.
- Bridging vs Terminal: It has 4 terminal methyl groups and 2 bridging methyl groups.
- The bridging carbon atoms lie in a plane with the two aluminum atoms, forming an Al-C-Al-C-tertacyclic ring.
- Hybridization: Both the aluminum and the carbon atoms are Sp3 hybridized.
- There are only 8 sp3 hybridization atoms present."
- Each Al atom contributes to sp3 hybridization (2 Al atoms), and each of the 6 carbon atoms in the CH3 groups also undergoes sp3 hybridization.
- All carbons of CH3 group do not lie in the same plane." - In the structure, the terminal CH3 groups are positioned above and below the plane formed by the bridging carbons.
- There are 52 bond electrons available." - Each CH3 group contributes 6 electrons (from 3-(C-H )bonds), and there are 6 (CH3 groups), contributing 6×6=36 electrons. The 4 Al-C bonds contribute 2×4= 8 electrons , and there are 2 Al- C-Al banana bonds contribute 2×2= 4 electrons. Thus, the total is (36+8+4 = 48 electrons,
