Calculation of number of 2c-2e bonds in Al2(CH3)6:

- The molecule Al2(CH3)6 can be divided into two Al(CH3)3 groups which are connected by a covalent bond between the two Al atoms.
- Each Al(CH3)3 group contains one Al atom, three CH3 groups, and three covalent bonds between the Al atom and the CH3 groups.
- Each covalent bond between the Al atom and a CH3 group is a 2-center-2-electron (2c-2e) bond, because it involves two atoms sharing two electrons.
- Therefore, each Al(CH3)3 group contains 3x2 = 6 2c-2e bonds.
- The two Al(CH3)3 groups are connected by a covalent bond between the two Al atoms, which is also a 2c-2e bond.
- Therefore, the molecule Al2(CH3)6 contains a total of 2x6 + 1 = 13 2c-2e bonds.
- However, each CH3 group also contains a covalent bond between the C atom and one of the H atoms, which is also a 2c-2e bond.
- Each Al(CH3)3 group contains 3 CH3 groups, so there are a total of 3x3 = 9 CH3 groups in the molecule.
- Therefore, there are 9 additional 2c-2e bonds in the molecule.
- Thus, the total number of 2c-2e bonds in Al2(CH3)6 is 13 + 9 = 22.