Question

Write the most stable Lewis structure (following formal charge rules) for the following molecules.

(a) SOCl2 [Hint: Sulfur is the central atom.]

(b) C2N2 [Hint: The two carbon atoms are connected in the middle of a chain.]

Answer 1

Lewis Structure

SOCl2

Sulfur is the central atom.

As we know sulfur can hold more than 8 valence electrons.

Sulfur has 6 valence electrons, Chlorine has 7 (we have two chlorines so 14) and Oxygen has 6.

Electron count equals 26. Sulfur is the central atom.

We need to put two electrons between each atom and remaining around the outside.

Formal charge on each atom should be ZERO. If formal charges are other than zero, then there is something wrong with the structure.

See Lewis structure in the image attached.

As we know formal charges should be zero. Lets try different configuration as example double bonds.

C2N2

This is rather interesting structure. We should always remember that least electronegative atom is the central one. Here it is Carbon.

Carbon has 4 valence electrons and N has 5.

This structure has C-N triple bond.

See Lewis structure in the image attached.

Formal charges should always be zero.