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Ammonia boron trifluoride adduct Lewis Structure

Ammonia boron trifluoride adduct Lewis structure (H3BF3N). N–B single bond and 3 N–H single bond. It shows a tetrahedral shape, sp3 hybridization on N, 109.5° bond angles. Count 32 valence electrons and a tetrahedral electron-domain arrangement. Abelson3 MIN READSeptember 30, 2026

Ammonia boron trifluoride adduct Lewis Structure: H3BF3N Lewis Structure, tetrahedral Geometry, sp3 Hybridization & Polarity

Ammonia boron trifluoride adduct Lewis structure Cover

Ammonia boron trifluoride adduct Key Facts

The Ammonia boron trifluoride adduct Lewis structure is N–B single bond and 3 N–H single bond; the central N has 4 electron domains (0 lone pairs), giving a tetrahedral electron-domain arrangement and a tetrahedral molecular geometry with a 109.5° bond angle. N is best described as sp3-hybridized, and Ammonia boron trifluoride adduct is polar because the tetrahedral shape (and/or unequal terminal atoms) prevents cancellation of the bond dipoles.

Ammonia boron trifluoride adduct Lewis Structure Figure 1: Lewis Structure of Ammonia boron trifluoride adduct (H3BF3N)
Chemical Formula H3BF3N
CAS Number 13521-80-3
Total Valence Electrons 32
Lewis Structure N–B single bond and 3 N–H single bond
Electron-Domain Geometry tetrahedral
Molecular Geometry tetrahedral
Hybridization Model sp3 (central N)
Bond Angle 109.5°
Polarity Polar molecule
PubChem and NIST list Ammonia boron trifluoride adduct as H 3BF 3N with CAS 13521-80-3; molecular weight ≈ None g/mol. View CAS 13521-80-3 dictionary details on Guidechem →

Applications of Ammonia boron trifluoride adduct (CAS 13521-80-3)

As a hydride of N, Ammonia boron trifluoride adduct is typically a strong reducing agent, a potential fuel component, or a precursor in inorganic and organometallic synthesis. Many pnictogen/sulfur hydrides are toxic, foul-smelling and pyrophoric or flammable, and are handled with appropriate ventilation and inert-atmosphere technique.

Reducing Agent Electron-rich hydrides reduce metal centers and functional groups in synthesis.
Precursor / Feedstock Source of N in the preparation of derivatives and doped materials.
Handling Often toxic/flammable/pyrophoric; inert atmosphere and active ventilation required.
Procurement Note "Ammonia boron trifluoride adduct" is supplied in multiple commercial grades and package sizes. Specify purity, grade, moisture/impurity limits, package (cylinder, drum or bulk) and intended process, and use CAS 13521-80-3 as the primary identifier when screening suppliers; always confirm regional availability and safety documentation (SDS).

Step 1 - Valence Electrons & Central Atom

To draw the Ammonia boron trifluoride adduct Lewis structure we first count the total valence electrons. H3BF3N contains 3×1 (H) + 3 (B) + 3×7 (F) + 5 (N); the net charge of 0 gives a total of 32 valence electrons to place.

The central atom is N. 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).

Valence-electron count

Total valence electrons = 3×1 (H) + 3 (B) + 3×7 (F) + 5 (N) = 32 electrons.

Step 2 - Lewis Structure & Electron Distribution

Place N 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: N–B single bond and 3 N–H single bond; no lone pairs on N.

Counting bonding and nonbonding electrons around N therefore satisfies the octet/expanded-octet requirement for the drawn structure.

N–B N–H ×3
N: 0 lone pairs, 4 bonding domains
4 bonding domains + 0 lone pairs = 4 electron domains
Octet Rule: Why N Has Eight Electrons N forms 4 bond(s) and retains 0 nonbonding electron(s), reaching an octet. No expanded octet is required for this second-row (or octet-satisfying) central atom.

Step 3 - VSEPR Theory & Geometry

VSEPR theory states that the 4 electron domains around N arrange to minimize mutual repulsion, giving an tetrahedral electron-domain geometry.

Because 0 of these domains are lone pair(s) — and lone pairs repel more strongly than bonding pairs — the observed molecular geometry is tetrahedral; the N bond angle is set to 109.5° rather than the ideal value for the electron-domain geometry.

Repulsion hierarchy

A useful VSEPR approximation is: lone pair–lone pair repulsion > lone pair–bonding pair repulsion > bonding pair–bonding pair repulsion. With 0 lone pair(s) on N, the lone-pair domains occupy positions that minimize overall repulsion while pushing the bonding domains (and therefore the bonded atoms) closer together.

Hybridization & Formal Charge

In the conventional localized-bond model, N uses sp3 hybrid orbitals to form the 4 equivalent electron-domain directions (4 bonding + 0 lone pair).

Formal-charge check

Formal charge on central N = V − N − ½B = 5 − 0 − ½×8 = 4. The nonzero formal charge is distributed by resonance / charge separation; the drawn structure is the lowest-energy contributor.

Modeling Note Modeling Note: sp3 is a compact model for the 4 electron-domain directions around N; full quantum-chemical treatments use molecular orbitals.

Is Ammonia boron trifluoride adduct Polar or Nonpolar?

Ammonia boron trifluoride adduct is polar. The tetrahedral 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.

Expert Quote — Structural Chemistry Perspective

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 Ammonia boron trifluoride adduct the tetrahedral 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.

Structural Comparison Table

Species Formula Central Atom Electron Domains Molecular Geometry Polarity
Ammonia boron trifluoride adduct H3BF3N N 4 tetrahedral Polar
Ammonia H3N N 4 trigonal pyramidal Polar
Ammonium H4N N 4 tetrahedral Nonpolar
Hydrazine H4N2 N 4 trigonal pyramidal Polar
Nitrogen N2 N 2 linear (diatomic) Nonpolar
Nitric oxide NO N 3 linear (diatomic) Polar
Practice question Starting from the 32 valence electrons of H3BF3N, draw the Lewis structure and confirm the central N atom is sp3-hybridized with tetrahedral geometry. What happens to the bond angle if one terminal atom is replaced by a more electronegative substituent?
Looking for industrial bulk or specified-grade supplies of Ammonia boron trifluoride adduct (CAS 13521-80-3)? Browse Supplier on Guidechem →

FAQs

Is H3BF3N polar or nonpolar?

Ammonia boron trifluoride adduct is polar. Its tetrahedral geometry (and/or unequal terminal atoms) stops the bond dipoles from cancelling.

What is the Lewis structure of Ammonia boron trifluoride adduct?

N–B single bond and 3 N–H single bond; no lone pairs on N. It uses all 32 valence electrons and the preferred structure carries a formal charge of 4 on the central atom.

What is the bond angle in Ammonia boron trifluoride adduct?

The N angle is about 109.5°. Lone-pair repulsion compresses the angle from the ideal tetrahedral value.

What is the hybridization of N in Ammonia boron trifluoride adduct?

The conventional model is sp3. Ammonia boron trifluoride adduct has 4 electron domains around the central N.

What is the CAS number of Ammonia boron trifluoride adduct?

The CAS number is 13521-80-3. PubChem and NIST identify this with H3BF3N; use it to locate suppliers and database records.

References

  1. PubChem, Ammonia boron trifluoride adduct. Molecular formula, CAS number, molecular weight and chemical identity.
  2. NIST Chemistry WebBook, SRD 69, Ammonia boron trifluoride adduct. Formula, CAS Registry Number and thermochemical / spectroscopic data.
  3. IUPAC Gold Book. Definitions for "lone pair", "VSEPR", "hybridization" and "formal charge".
  4. Atkins, P. & de Paula, J., Physical Chemistry. VSEPR, molecular geometry and dipole moments.
  5. Guidechem supplier & dictionary records. Commercial sourcing and CAS-linked property pages for Ammonia boron trifluoride adduct (CAS 13521-80-3).

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 13521-80-3 identifies the substance, not a universal purity specification.

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