How many electrons are involved in #sigma-"bonding"# in the #"acetylene"# molecule?

1 Answer

Well, formally, there are 6 electrons involved in the #sigma-"bonding interaction"#. No?

Explanation:

We gots #"acetylene"#, #H-C-=C-H#. There are #2xxC-H# bonds, and #1xxC-C# bond, and each bond formally requires 2 electrons, and thus there are 6 electrons involved.

Of course there are #2xxC-C# #pi# bonds above and below the plane of the #sigma-"bonds"# in 3 dimensions.