The Boron monofluoride Lewis structure is a linear diatomic with a polar bond between its two atoms; because the two atoms differ in electronegativity, Boron monofluoride is polar.
Figure 1: Lewis Structure of Boron monofluoride (BF)
| Chemical Formula | BF |
| CAS Number | 13768-60-0 |
| Total Valence Electrons | 10 |
| Lewis Structure | linear diatomic molecule with one single bond and a lone pair on each atom |
| Electron-Domain Geometry | linear |
| Molecular Geometry | linear (diatomic) |
| Hybridization Model | sp |
| Bond Angle | 180° |
| Polarity | Polar molecule |
Boron monofluoride is encountered as a reagent, intermediate or specialty chemical in inorganic, organometallic and materials synthesis. Confirm grade, purity and supplier documentation (SDS) before specifying for a process.
To draw the Boron monofluoride Lewis structure we first count the total valence electrons. BF contains 3 (B) + 7 (F); the net charge of 0 gives a total of 10 valence electrons to place.
The central atom is B. It is the least electronegative atom capable of forming multiple bonds and is surrounded by the more electronegative terminal atom(s); hydrogen, when present, always occupies a terminal position. Electronegativity considerations place the electron density toward the terminal atom(s).
Total valence electrons = 3 (B) + 7 (F) = 10 electrons.
Place B at the center and connect each surrounding atom with a single bond, complete octets on the terminal atoms, and place any remaining electrons on the central atom. The resulting electron distribution is: linear diatomic molecule with one single bond and a lone pair on each atom.
Counting bonding and nonbonding electrons around B therefore satisfies the octet/expanded-octet requirement for the drawn structure.
VSEPR theory states that the 2 electron domains around B arrange to minimize mutual repulsion, giving an linear electron-domain geometry.
Because 1 of these domains are lone pair(s) — and lone pairs repel more strongly than bonding pairs — the observed molecular geometry is linear (diatomic); the B bond angle is set to 180° rather than the ideal value for the electron-domain geometry.
A useful VSEPR approximation is: lone pair–lone pair repulsion > lone pair–bonding pair repulsion > bonding pair–bonding pair repulsion. With 1 lone pair(s) on B, the lone-pair domains occupy positions that minimize overall repulsion while pushing the bonding domains (and therefore the bonded atoms) closer together.
In the conventional localized-bond model, B uses sp hybrid orbitals to form the 2 equivalent electron-domain directions (1 bonding + 1 lone pair).
Formal charge on central B = V − N − ½B = 3 − 2 − ½×2 = 0. The preferred Lewis structure carries zero formal charge on the central atom (and on the terminals), so it is the dominant contributor.
Boron monofluoride is polar. The linear (diatomic) shape prevents cancellation of the bond dipoles. The bond dipoles do not cancel, leaving a net molecular dipole, which strongly influences solvation behavior and intermolecular interactions.
The decisive structural fact is not simply that the individual bonds are polar; it is whether molecular symmetry allows their vector sum to vanish. In Boron monofluoride the linear (diatomic) arrangement prevents cancellation, so a permanent dipole remains.
Interpretation consistent with standard VSEPR / molecular-geometry references.This polarity profile underpins its behavior as a solvent, reactant or process intermediate; when sourcing, specify grade and container compatibility.
| Species | Formula | Central Atom | Electron Domains | Molecular Geometry | Polarity |
|---|---|---|---|---|---|
| Boron monofluoride | BF | B | 2 | linear (diatomic) | Polar |
| Boron trifluoride | BF3 | B | 3 | trigonal planar | Nonpolar |
| Boron trichloride | BCl3 | B | 3 | trigonal planar | Nonpolar |
| Diborane | B2H6 | B | 3 | trigonal planar | Polar |
Boron monofluoride is polar. Its linear (diatomic) geometry (and/or unequal terminal atoms) stops the bond dipoles from cancelling.
linear diatomic molecule with one single bond and a lone pair on each atom. It uses all 10 valence electrons and the preferred structure carries zero formal charge on the central atom.
The B angle is about 180°. Lone-pair repulsion compresses the angle from the ideal linear value.
The conventional model is sp. Boron monofluoride has 2 electron domains around the central B.
The CAS number is 13768-60-0. PubChem (CID 6336604) and NIST identify this with BF; use it to locate suppliers and database records.
Technical scope: Lewis structures, VSEPR and hybridization are model-based descriptions for chemical communication and structure prediction; actual molecular electronic structure is more accurately represented by molecular-orbital and quantum-chemical methods. Commercial grades vary substantially by supplier and intended use; CAS 13768-60-0 identifies the substance, not a universal purity specification.
![]() |
![]() |