How are non polar covalent bonds formed?

Question

Emilia Alvarez · Accepted Answer

Actually, all covalent bonds between different atoms are polar to some extent......

Because more electronegative atoms tend to pull electron charge density towards themselves, creating a partial negative charge (and consequently a partial positive charge on the other atom), the greater the difference in electronegativity between the atoms in a covalent bond, the more polar the bond. Therefore, for binary compounds in order to have a truly non-polar covalent bond the two atoms should be identical. Therefore, the bonds in such things as #O_2# or #Cl_2# are non polar bonds. The bond between hydrogen and chlorine in HCl, however, is polar, as hydrogen is less electronegative than chlorine. For more complex molecules, the degree of polarity in a bond will be influenced by the nature of the groups bonded to each atom. Therefore in methanol, #CH_3OH# the C-O bond is polar as oxygen is more electronegative than carbon. But in propanol #CH_3-CH_2-CH_2-OH# the C-O bond is still polar, but less so, due to the ethyl group having an inductive effect which pushes charge density back towards the oxygen atom. To complicate things further, symmetry plays a part too. Therefore, whilst the bond between carbon and oxygen in #CO_2# is polar, the fact that the molecule is linear means that the polarity of the two C=O bonds cancel each other out. So overall the molecule is not polar (although the two bonds, separately, are). All right now? hehe

Nicholas Antonuccio · Answer

undefined Nonpolar covalent bonds are formed when two atoms share electrons equally due to similar electronegativities. This occurs when atoms of the same element bond or when atoms of different elements with similar electronegativities bond.