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Geometric Isomers — 3D Molecular Explorer

ORGANIC CHEMISTRY · CIS-TRANS ISOMERISM · DOUBLE BOND RESTRICTION

📚Teaching Guide▼

What Are Geometric Isomers?

Geometric (cis-trans) isomers share the same molecular formula and bond connectivity, but differ in the spatial arrangement of groups around a restricted bond — typically a C=C double bond.

Why Can't the Double Bond Rotate?

A C=C double bond consists of a σ (sigma) bond and a π (pi) bond. Rotation would break the π bond, requiring ~250 kJ/mol — so substituents are locked in place at room temperature.

🔵 Cis: similar groups on the same side of the double bond → bent chain

🟠 Trans: similar groups on opposite sides → more linear chain

Requirements

Each carbon of the C=C must have two different substituents. If either carbon has two identical groups, no geometric isomers exist.

Physical Property Differences

🌡 Cis isomers are often more polar (dipoles add) → higher boiling points in simple cases.

❄️ Trans isomers often pack better in crystals → higher melting points.

How to Use This Simulator

Select a molecule pair below. Drag to rotate each model. Scroll to zoom. Watch how the chain bends differently in cis vs trans!

Select Molecule Pair

3-Hexene (C₆H₁₂)

2-Hexene (C₆H₁₂)

4-Methyl-2-hexene (C₇H₁₄)

Atom Legend

Carbon (C)

Hydrogen (H)

Methyl Branch C

C=C double bond

Drag → rotate · Scroll → zoom

SPEED

CIScis-3-hexeneC₆H₁₂

cis-3-hexene

Both ethyl groups on SAME side of C=C

TRANStrans-3-hexeneC₆H₁₂

trans-3-hexene

Both ethyl groups on OPPOSITE sides

PAIR

3-Hexene

DOUBLE BOND

C3=C4

CIS BOILING PT

66°C

TRANS BOILING PT

67°C

KEY DIFFERENCE: cis has a bent chain — trans is more linear and extended.