Question

why dont carbon share it's 4 electrons with another carbon atom creating 4 covalent bonds between 2 carbon atoms to complete the octet.

Answer 1

carbon actually shares its electrons with carbon and this process is known as catanation and this is the reason for carbon long chained compounds.but carbon is electronegetive so it. needs electrons and due to this carbon cannot share it's electrons with only carbon it need more elements.