Two pi and half sigma bonds are present in:

🧠 "Two pi and half sigma" means: 2 complete π bonds + 0.5 σ bond from the net MO contributions.

🗺️ $\mathrm{N_2^+}$ (13 electrons, N₂-type ordering):

\sigma_{1s}^2\sigma^*_{1s}^2\sigma_{2s}^2\sigma^*_{2s}^2\pi_{2p_x}^2\pi_{2p_y}^2\sigma_{2p_z}^1

Net σ contribution: \sigma_{2s}^2(+1) + \sigma^*_{2s}^2(-1) + \sigma_{2p_z}^1(+0.5) = 0.5 σ bond

Net π contribution: $\pi_{2p_x}^2(+1) + \pi_{2p_y}^2(+1) = 2$ π bonds

Total BO = $0.5 + 2 = 2.5$ ✓

⚡ For comparison — $\mathrm{N_2}$ has 1σ + 2π (integer bonds), and $\mathrm{O_2^-}$ has fractional π character. Only $\mathrm{N_2^+}$ gives exactly two pi and half sigma.

$\boxed{\text{Answer: } \mathrm{N_2^+}}$