Is carbon diatomic?
Apparently it can happen but its not very common, so for all intensive purposes no.
A molecule made up of two atoms is called a diatomic molecule. A diatomic molecule can be composed of two of the same atoms, called a diatomic element. Hydrogen gas, H2, is an example of a diatomic element. A diatomic molecule can also be a compound composed of two atoms of different elements, such as carbon monoxide, CO.