Boron Trichloride overview
The stored Lewis connectivity is Cl₃B. Boron has only six electrons around it in the standard monomeric Lewis structure, making BCl₃ an octet exception and Lewis acid.
How to draw BCl₃
- Count 24 valence electrons. Include charge adjustments before drawing.
- Use the reviewed connectivity Cl₃B. Do not infer a different isomer from the formula alone.
- Place the required single, double or multiple bonds. Keep a running electron total.
- Complete terminal valence shells and add lone pairs or formal charges. Boron has only six electrons around it in the standard monomeric Lewis structure, making BCl₃ an octet exception and Lewis acid.
- Verify the total electron count and geometry. The reviewed geometry is Trigonal planar, 120°.
Why this example matters
Boron has only six electrons around it in the standard monomeric Lewis structure, making BCl₃ an octet exception and Lewis acid.
Scope and model limits
The monomeric classroom structure is shown. Lewis-acid adducts can give boron a complete octet.
Common mistakes
- Adding a lone pair to boron
- Forcing B=Cl double bonds
- Calling the molecule trigonal pyramidal
Related reviewed guides
Last reviewed: 2026-07-16. Educational reference only; verify graded work with course materials.