Question

why does carbon not form four covalent bond ?

Answer 1

it can form four covalent bonds with other atoms and molecules

Answer 2

Answer:

The reason a carbonatom cannot bond withfour electrons with another carbon is due to the carbon electron orbitals. Since it has a s and 3 p orbitals, it must create one sigma and at most 2 pi bonds with anothercarbon. There's no spatial conditions for a 3rd pi bond, so it will have to be another sigma.