For the OCS Lewis structure, we have 6 valence
electrons for Oxygen, plus 4 for Carbon, and
6 for Sulfur for a total of 16 valence electrons
for the OCS Lewis structure. Carbon is the
least electronegative. We'll put that in the
center. We'll put the Oxygen on one side and
Sulfur on the other. We have 16 valence electrons for the OCS Lewis structure. We'll put 2 between
atoms to form chemical bonds; we've used four.
Then we'll go around the outside to fill the
octets on those atoms, or until we run out
of valence electrons. Two, 4, 6, and 16 valence
electrons. So we've used all 16 valence electrons.
The Sulfur and the Oxygen both have eight
valence electrons, so their octets are full,
but the Carbon in the center only has four
valence electrons. Let's take two valence
electrons here and share them with the Carbon
to form a double bond. The Sulfur still has
eight valence electrons, but now the Carbon
has six valence electrons and we're still
only using 16 valence electrons for the OCS
Lewis structure. Let's take these two here
and move them to the center, as well. Now
the Oxygen has eight valence electrons; but
the Carbon in the center also has eight valence
electrons, so it has an octet. Again, we're
still using only the 16 valence electrons
available for the OCS Lewis structure. So
that is the Lewis structure for OCS. This
is Dr. B., and thanks for watching.
