MO diagram for #"C"_2"^(2-)#?

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Answer 1 · 2017-11-15T16:39:32

Here's what I get.

We want to derive the MO diagram for #"C"_2^"2-"#.

Each #"C"# atom has 6 electrons, so the #"C"_2^"2-"# ion will contain 12 electrons plus 2 more to give the 2- charge.

Below is an MO energy level diagram for the diatomic entities of #"B, C"# and #"N"#.

MO Diagram
(Adapted from BC Open Textbooks)

We fill the boxes following the Aufbau Principle and Hund's Rule until we have added 14 electrons.

Thus, the sequence of molecular orbitals in #"C"_2^"2-"# is

#("σ1s")^2 ("σ*1s")^2color(white)(l) ("σ2s")^2 ("σ*2s")^2color(white)(l) ("π2p"_text(x))^2 ("π2p"_text(y))^2 "(σ2p"_text(z))^2#