What is the most preferable Lewis structure for S2Cl2?
The Correct Answer and Explanation is:
Most Preferable Lewis Structure for Disulfur Dichloride (S₂Cl₂):
The most preferable Lewis structure for S₂Cl₂ is:
CopyEditCl–S–S–Cl
Each sulfur atom has one single bond to the other sulfur atom and one single bond to a chlorine atom. Each chlorine atom has three lone pairs, and each sulfur atom has two lone pairs.
Explanation
The molecular formula S₂Cl₂ represents disulfur dichloride, a covalent compound composed of two sulfur atoms and two chlorine atoms. To draw the most preferable Lewis structure, we must follow standard electron-counting and formal charge minimization rules.
Step 1: Count total valence electrons.
- Sulfur (S) has 6 valence electrons × 2 = 12
- Chlorine (Cl) has 7 valence electrons × 2 = 14
- Total = 12 + 14 = 26 valence electrons
Step 2: Connect atoms with single bonds.
A common and reasonable starting point is a chain: Cl–S–S–Cl, where each S is singly bonded to another S and a Cl.
- S–S bond = 2 electrons
- Two S–Cl bonds = 2 × 2 = 4 electrons
- Total used so far: 6 electrons
Step 3: Distribute remaining electrons as lone pairs.
We have 26 – 6 = 20 electrons left.
- Each Cl needs 3 lone pairs (6 electrons × 2 = 12 electrons)
- Each S needs 2 lone pairs (4 electrons × 2 = 8 electrons)
- 12 + 8 = 20 electrons, matching perfectly.
Step 4: Check formal charges.
All atoms have formal charges of zero in this arrangement. This structure uses only single bonds and does not require expanded octets or formal charges, making it the most stable.
Step 5: Evaluate stability.
- Follows octet rule
- Minimizes formal charges
- Matches known experimental structure of S₂Cl₂
- Explains its bent geometry at S due to lone pairs
Therefore, Cl–S–S–Cl with lone pairs on each atom is the most preferable Lewis structure for S₂Cl₂.
