[s22345]

Why carbon doesn't share all it's four electrons with one carbon?

[sjb]

Why do you think it doesn't?

[Arkcon]

And form dicarbon, C₂?  Interesting idea.  What does it mean, "to share electrons"?  I mean really, what happens? Carbon can share one, two or three electrons: C-C, C=C, or C≡C, what happens, structurally, to the electron clouds, in those cases?  What would it mean to share 4 electrons?

I hope you don't mind, s22345:, me answering your question with more questions, but that's what we do here on the  Chemical Forums.  We detail that in our  Forum Rules{click}. You already accepted them when you signed up for our forum, and they apply to you, whether you agree with them or not, or even if you're unaware of them. 

You can find these concepts detailed in your text book, or even by searching this forum.

[Flatbutterfly]

One of the first reports of dicarbon, C₂, was that of Herzberg and Lagervist published in 1968.  They produced C₂ by the flash discharge of CH₄.  The bonding in C₂ is still a matter of controversy with a paper published in 2012 arguing that there is a CC quadruple bond in C₂.  It appears that this view is not generally accepted.  The conventional description using simple LCAO MO methods puts the CC bond order between 2 and 3 (i.e., between C=C and C≡C).  As this question was put out in the high school forum I assume that you are not familiar with the MO treatment of diatomic molecules as it is not covered until first or second year of university so perhaps we should stop here (but my compliments for thinking outside the box!).  If you are familiar with this treatment then draw out the MO treatment for N₂ (N≡N, ten valence electrons) and subtract two electrons and draw your conclusions.