According to molecular orbital theory which of the following is correct `:`

Options

A. `LUMO` level for `C_(2)` molecule is a `sigma 2p` orbital
B. In `C_(2)` molecule both the bonds are `pi` bonds
C. In `C_(2)^(2-)` ion there is one `sigma `and two `pi` bonds
D. all the above are correct.

Answer

4

Explanation

For `C_(2)` the electronic configuration is
`=sigma1S^(2),sigma^(**)1S^(2),sigma2S^(2),sigma^(**)2S^(2),pi2P_(x)^(2),pi2P_(y)^(2),sigma2P_(z)^(@)`
Hence the result follows.