carbon cannot form an ionic bond there are 4 electrons in the outermost shell and 6 protons in its nucleus. if it forms more than 3 bonds with an atom, it will form an ionic bond and complete its octet. read more
Lead can form a +4 ion, PbX4+, in compounds such as lead fluoride. The reason that this can happen but carbon cations cannot is that the outermost electrons in a lead atom are much farther from the nucleus than those of a carbon atom and are easier to remove as a result. CX4− ions: In gas form this does not happen. read more
Carbon has four valence electrons and to for am ionic compound, carbon should lose all the four electrons. This needs high ionisation energy and hence carbon generally shares electrons and forms covalent compounds. However carbon does form ionic compounds as in metal carbides. read more