Lewis Structure Generator
Acetylene · C2H2 · Reviewed guide

C2H2 Lewis Structure

Acetylene is H–C≡C–H. The carbon atoms share a triple bond, each carbon also bonds to one hydrogen, and the molecule is linear.

Open C2H2 in the generatorSee drawing steps
C₂H₂
H–C≡C–H
A carbon-carbon triple bond and no carbon lone pairs
Valence electrons10
C–C bondTriple
Geometry at CLinear
Bond angle180°

How to draw C2H2

  1. Count 10 electrons.
    Two carbons contribute 8 and two hydrogens contribute 2.
  2. Use H–C–C–H connectivity.
    Hydrogen must be terminal.
  3. Draw three single bonds.
    This uses 6 electrons but leaves both carbons short of octets.
  4. Convert the C–C bond to a triple bond.
    Add two more shared pairs between carbon atoms.
  5. Verify the total.
    The two C–H bonds and one C≡C bond use all 10 electrons.

Formal charges

Each carbon owns four bonding pairs and has formal charge zero. Each hydrogen also has formal charge zero.

Geometry

Each carbon has two electron domains: one C–H bond and one C≡C bonding region. VSEPR therefore predicts a linear 180° arrangement.

Common mistakes

  • Drawing a C=C double bond and leaving both carbons incomplete.
  • Adding lone pairs to carbon in the final structure.
  • Placing both hydrogens on the same carbon when the intended compound is acetylene.

Reviewed July 16, 2026. Educational reference only.