organic chemistry - Carbon with 5 bonds?

I've heard that, even though according to Molecular Orbital Theory there is no chance of having nobel gases bonded to each other, it is not totally impossible. For example, under extreme conditions, Ar2 can be synthesised.

So I am wondering whether a carbon can make 5 bonds if the required conditions are provided.

Answer

Carbon cannot have more then 4 double-electron bonds in reasonable conditions. However, in can form a bond with 5 or 6 atoms, like $\ce{Fe6C}$ fragment, where iron atoms form octahedron around the carbon atom. However, the sum of orders of 6 $\ce{C-Fe}$ bonds will be still 4.

The situation is different if we consider exited states. Indeed, it is possible for hight excited state of carbon to be able to form 5 or 6 bonds. The resulting structure, however, will die quickly.

Noble gases are able to form molecules in excited states, or, to be precise, their molecules are stable only in excited state. This kind of molecules is known as excimer (excited dimer).