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Disulfide ion (S₂²⁻) Lewis structure

14 valence electrons, linear, a charge of −2

S S − − 2−
S₂²⁻ as the Lewis Structure Generator draws it: lone pairs as dots, nonzero formal charges circled.

Build S₂²⁻ step by step in the Lewis Structure Generator

What is the Lewis structure of S₂²⁻?

Disulfide ion, S₂²⁻, has 2 × 6 + 2 = 14 valence electrons. Its two atoms are joined by one S−S single bond. It carries three lone pairs on each S. Its formal charges are −1 on each S. As two atoms it is linear.

Valence electrons in S₂²⁻

Element Group Valence electrons Atoms Electrons
Sulfur 16 6 2 12
Charge of 2− +2
Total 14

In one line: 2 × 6 + 2 = 14. Each atom brings the valence electrons its group gives it, and the negative charge adds one electron for each unit.

How to draw the S₂²⁻ Lewis structure

  1. Count the valence electrons. Valence electrons: each S 6, and the 2− charge adds 2. 2 × 6 + 2 = 14.
  2. Join the two atoms. With only two atoms there is no choice to make: they bond to each other.
  3. Join the atoms with single bonds. One single bond uses 2 electrons, leaving 14 − 2 = 12.
  4. Place the lone pairs. Neither atom is an outer one, so the 12 left go on the two atoms as three lone pairs on each S. Now each S has 8 electrons round it.
  5. Make multiple bonds where needed. Each S already has an octet, so no lone pair needs to become a bond.

Lone pairs and formal charges in S₂²⁻

Atom Number Bonds Lone pairs Electrons round it Formal charge, V − N − B/2
S 2 one single bond 3 8 6 − 6 − 1 = −1

V is the atom’s valence electrons, N its nonbonding electrons and B its bonding electrons. The formal charges add up to −2, the charge on the ion.

Shape and polarity of S₂²⁻

Central atom none, two atoms
Electron geometry linear
Molecular geometry linear
Ideal bond angle none, two atoms
Polarity, an estimate not applicable

An ion carries a net charge, so whether its bond dipoles cancel is not the question polarity asks.

Work with S₂²⁻