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Acetyl radical Lewis Structure

Acetyl radical Lewis structure (C2H3O). C–C single bond and 3 C–H single bond. It shows a tetrahedral shape, sp3 hybridization on C, 109.5° bond angles. Count 17 valence electrons and a tetrahedral electron-domain arrangement. Polarity: Polar. Jacob3 MIN READSeptember 30, 2026

Acetyl radical Lewis Structure: C2H3O Lewis Structure, tetrahedral Geometry, sp3 Hybridization & Polarity

Acetyl radical Lewis structure Cover

Acetyl radical Key Facts

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

Acetyl radical Lewis Structure Figure 1: Lewis Structure of Acetyl radical (C2H3O)
Chemical Formula C2H3O
CAS Number 3170-70-5
Total Valence Electrons 17
Lewis Structure C–C single bond and 3 C–H single bond
Electron-Domain Geometry tetrahedral
Molecular Geometry tetrahedral
Hybridization Model sp3 (central C)
Bond Angle 109.5°
Polarity Polar molecule
PubChem and NIST list Acetyl radical as C 2H 3O with CAS 3170-70-5; molecular weight ≈ None g/mol. View CAS 3170-70-5 dictionary details on Guidechem →

Applications of Acetyl radical (CAS 3170-70-5)

This organic compound is used as a solvent, intermediate or specialty reagent in fine-chemical, pharmaceutical and materials synthesis; specify grade and impurity profile when sourcing.

Solvent / Reagent Medium for reactions, extraction or formulation.
Intermediate Building block for downstream derivatives.
Specialty Use Targeted role in pharma/fragrance/materials.
Procurement Note "Acetyl radical" 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 3170-70-5 as the primary identifier when screening suppliers; always confirm regional availability and safety documentation (SDS).

Step 1 - Valence Electrons & Central Atom

To draw the Acetyl radical Lewis structure we first count the total valence electrons. C2H3O contains 2×4 (C) + 3×1 (H) + 6 (O); the net charge of 0 gives a total of 17 valence electrons to place.

The central atom is C. 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 = 2×4 (C) + 3×1 (H) + 6 (O) = 17 electrons.

Step 2 - Lewis Structure & Electron Distribution

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

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

C–C C–H ×3
C: 0 lone pairs, 4 bonding domains
4 bonding domains + 0 lone pairs = 4 electron domains
Octet Rule: Why C Has Eight Electrons C 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 C 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 C 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 C, 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, C uses sp3 hybrid orbitals to form the 4 equivalent electron-domain directions (4 bonding + 0 lone pair).

Formal-charge check

Formal charge on central C = V − N − ½B = 4 − 0 − ½×8 = 3. 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 C; full quantum-chemical treatments use molecular orbitals.

Is Acetyl radical Polar or Nonpolar?

Acetyl radical 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 Acetyl radical 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
Acetyl radical C2H3O C 4 tetrahedral Polar
Carbon dioxide CO2 C 2 linear Nonpolar
Carbon monoxide CO C 2 linear (diatomic) Polar
Carbon disulfide CS2 C 2 linear Nonpolar
Methane CH4 C 4 tetrahedral Nonpolar
Ethane C2H6 C 4 tetrahedral Nonpolar
Practice question Starting from the 17 valence electrons of C2H3O, draw the Lewis structure and confirm the central C 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 Acetyl radical (CAS 3170-70-5)? Browse Supplier on Guidechem →

FAQs

Is C2H3O polar or nonpolar?

Acetyl radical is polar. Its tetrahedral geometry (and/or unequal terminal atoms) stops the bond dipoles from cancelling.

What is the Lewis structure of Acetyl radical?

C–C single bond and 3 C–H single bond; no lone pairs on C. It uses all 17 valence electrons and the preferred structure carries a formal charge of 3 on the central atom.

What is the bond angle in Acetyl radical?

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

What is the hybridization of C in Acetyl radical?

The conventional model is sp3. Acetyl radical has 4 electron domains around the central C.

What is the CAS number of Acetyl radical?

The CAS number is 3170-70-5. PubChem and NIST identify this with C2H3O; use it to locate suppliers and database records.

References

  1. PubChem, Acetyl radical. Molecular formula, CAS number, molecular weight and chemical identity.
  2. NIST Chemistry WebBook, SRD 69, Acetyl radical. 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 Acetyl radical (CAS 3170-70-5).

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 3170-70-5 identifies the substance, not a universal purity specification.

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