How would you contrast single covalent bonds?

Question

Jacob Anderson · Accepted Answer

Well, let us contrast them on the basis of polarity.....

The charge separation of the electron density between the bound atoms is reflected by polarity. Homonuclear diatomic molecules, such as #H-H#, and #X-X#, dihydrogen, and the halogens are necessarily NON-POLAR because the bound atoms have the same electronegativity and thus electron density is shared equally...Bond polarity is also not a feature of the wealth of carbon chemistry, due to the small difference in electronegativity of carbon and hydrogen....and the capacity of carbon to catenate....to form long #C-C# chains, along which substitution by heteroatoms can occur. When two or more non-polar atoms are bound, say between #H-F# or #H-O-H#, bond polarity manifests due to the difference in bond polarity, and this is the origin of intermolecular hydrogen bonding, i.e. on the back of dipole-dipole interactions.... #""^(+delta)H-F^(delta-)#, and #""^(+delta)H_2O^(delta-)#. Of course this represents the extreme end of polar bond..... THE bond in say #H_2S#, #Br-Cl# would display much less charge separation, and much less polarity....because the bound atoms have a SMALLER difference in electronegativity.

Easton Jones · Answer

undefined Single covalent bonds involve the sharing of one pair of electrons between two atoms, while double covalent bonds involve the sharing of two pairs of electrons between two atoms.