Question

Which of the following options represents the correct bond order?

Options

• \[\ce{O^{-}2 > O2 > O^{+}2}\]

• \[\ce{O^{-}2 < O2 < O^{+}2}\]

• \[\ce{O^{-}2 > O2 < O^{+}2}\]

• \[\ce{O^{-}2 < O2 > O^{+}2}\]

Answer 1

\[\ce{O^{-}2 < O2 < O^{+}2}\]

Explanation:

The electronic configurations and the bond orders of the given species are given below:

Bond order of \[\ce{O^{-}2}\]:

Electronic configuration:

`σ1s^2, σ^∗1s^2, σ2s^2, σ^∗2s^2, σ2p_z^2 (π2p_x^2 = 2p_y^2)(π^∗2p_x^1 = π^∗2p_y^1)`

Bond order = `1/2 (N_b - N_a)`

BO = `1/2(10 - 7) = 3/2 = 1.5`

Bond order of \[\ce{O^{+}2}\]:

Electronic configuration:

`σ1s^2, σ^∗1s^2, σ2s^2, σ^∗2s^2, σ2p_z^2 (π2p_x^2 = 2p_y^2)(π^∗2p_x^1 = π^∗2p_y^0)`

BO = `1/2(10 - 5) = 5/2 = 2.5`

Bond order of  \[\ce{O2}\]:

Electronic configuration:

`σ1s^2, σ^∗1s^2, σ2s^2, σ^∗2s^2, σ2p_z^2 (π2p_x^2 = 2p_y^2)(π^∗2p_x^1 = π^∗2p_y^1)`

BO = `(10 - 6)/2 = 4/2 = 2`