Dot structures| Lewis : Thionyl chloride #57

A simple procedure for writing Lewis electron dot structures (LEDS) was given in a previous article entitled “Lewis Structures and the Octet Rule”.

Several worked examples relevant to this procedure were given in previous posts please see the Sitemap - Table of Contents (Lewis Electron Dot Structures)

Let us consider the case thionyl chloride SOCl₂. Thionyl chloride is primarily used as a chlorinating agent. It is toxic and reacts violently with water. It is used in the industrial production of organochlorine compounds which are often indermetiates in pharmaceuticals and agrochemicals. It is a component of lithium-thionyl chloride batteries where it acts as the positive electrode.
How can we construct the Lewis dot structure?

 

Step 1: Connect the atoms with single bonds. The less electronegative is the sulfur atom. Hence, the S atom is going to be the central atom.

Fig. 1 : Connect the atoms of SOCl₂ with single bonds.

Step 2:  Calculate the # of electrons in π bonds (multiple bonds) using  formula (1):

 Where n in this case is 4. Where V = (6 +6 + 7 +7)  = 26 , V is the number of valence electrons of the thionyl chloride molecule.

Therefore, P = 6n + 2 – V = 6 * 4 + 2 – 26  = 0     So, there is no double bond.

Step 3 & 4: The  Lewis resonance structures of SOCl₂ are as follows:

Fig. 2 : Lewis electron structure of SOCl₂ – the most plausible structure is shown.