Hydroperoxyl radical Lewis Structure

Hydroperoxyl radical Lewis Structure: HO₂ Lewis Structure, bent Geometry, sp3 Hybridization & Polarity

Hydroperoxyl radical Key Facts

The Hydroperoxyl radical Lewis structure is O–O single bond and O–H single bond; the central O has 4 electron domains (2 lone pairs), giving a tetrahedral electron-domain arrangement and a bent molecular geometry with a ≈104.5° bond angle. O is best described as sp3-hybridized, and Hydroperoxyl radical is polar because the bent shape (and/or unequal terminal atoms) prevents cancellation of the bond dipoles.

Figure 1: Lewis Structure of Hydroperoxyl radical (HO₂)

Chemical Formula	HO₂
CAS Number	3170-83-0
Total Valence Electrons	13
Lewis Structure	O–O single bond and O–H single bond
Electron-Domain Geometry	tetrahedral
Molecular Geometry	bent
Hybridization Model	sp3 (central O)
Bond Angle	≈104.5°
Polarity	Polar molecule

PubChem (CID 520535) and NIST list Hydroperoxyl radical as HO ₂ with CAS 3170-83-0; molecular weight ≈ 33.007 g/mol. View CAS 3170-83-0 dictionary details on Guidechem →

Applications of Hydroperoxyl radical (CAS 3170-83-0)

Hydroperoxyl radical 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.

Reagent / Intermediate Used in synthesis and formulation where the substance's reactivity is required.

Specialty Chemical Specified by grade for the intended process or research use.

Sourcing Verify purity, package and regional availability via the CAS identifier.

Procurement Note "Hydroperoxyl 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 3170-83-0 as the primary identifier when screening suppliers; always confirm regional availability and safety documentation (SDS).

Step 1 - Valence Electrons & Central Atom

To draw the Hydroperoxyl radical Lewis structure we first count the total valence electrons. HO₂ contains 1 (H) + 2×6 (O); the net charge of 0 gives a total of 13 valence electrons to place.

The central atom is O. 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 = 1 (H) + 2×6 (O) = 13 electrons.

Step 2 - Lewis Structure & Electron Distribution

Place O 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: O–O single bond and O–H single bond; 2 lone pairs on O.

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

O–O O–H

O: 2 lone pairs, 2 bonding domains

2 bonding domains + 2 lone pairs = 4 electron domains

Octet Rule: Why O Has Eight Electrons O forms 2 bond(s) and retains 4 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 O arrange to minimize mutual repulsion, giving an tetrahedral electron-domain geometry.

Because 2 of these domains are lone pair(s) — and lone pairs repel more strongly than bonding pairs — the observed molecular geometry is bent; the O bond angle is set to ≈104.5° 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 2 lone pair(s) on O, 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, O uses sp3 hybrid orbitals to form the 4 equivalent electron-domain directions (2 bonding + 2 lone pair).

Formal-charge check

Formal charge on central O = V − N − ½B = 6 − 4 − ½×4 = 1. 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 O; full quantum-chemical treatments use molecular orbitals.

Is Hydroperoxyl radical Polar or Nonpolar?

Hydroperoxyl radical is polar. The bent 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 Hydroperoxyl radical the bent 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
Hydroperoxyl radical	HO₂	O	4	bent	Polar
Water	H₂O	O	4	bent	Polar
Hydrogen peroxide	H₂O₂	O	4	bent	Polar
Ozone	O₃	O	3	bent	Polar
Hydronium	H₃O	O	4	trigonal pyramidal	Polar
Hypochlorite	ClO	O	4	linear (diatomic)	Polar

Practice question Starting from the 13 valence electrons of HO₂, draw the Lewis structure and confirm the central O atom is sp3-hybridized with bent 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 Hydroperoxyl radical (CAS 3170-83-0)? Browse Supplier on Guidechem →

FAQs

Is HO₂ polar or nonpolar?

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

What is the Lewis structure of Hydroperoxyl radical?

O–O single bond and O–H single bond; 2 lone pairs on O. It uses all 13 valence electrons and the preferred structure carries a formal charge of 1 on the central atom.

What is the bond angle in Hydroperoxyl radical?

The O angle is about ≈104.5°. Lone-pair repulsion compresses the angle from the ideal tetrahedral value.

What is the hybridization of O in Hydroperoxyl radical?

The conventional model is sp3. Hydroperoxyl radical has 4 electron domains around the central O.

What is the CAS number of Hydroperoxyl radical?

The CAS number is 3170-83-0. PubChem (CID 520535) and NIST identify this with HO₂; use it to locate suppliers and database records.

References

PubChem CID 520535, Hydroperoxyl radical. Molecular formula, CAS number, molecular weight and chemical identity.
NIST Chemistry WebBook, SRD 69, Hydroperoxyl radical. Formula, CAS Registry Number and thermochemical / spectroscopic data.
IUPAC Gold Book. Definitions for "lone pair", "VSEPR", "hybridization" and "formal charge".
Atkins, P. & de Paula, J., Physical Chemistry. VSEPR, molecular geometry and dipole moments.
Guidechem supplier & dictionary records. Commercial sourcing and CAS-linked property pages for Hydroperoxyl radical (CAS 3170-83-0).

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 3170-83-0 identifies the substance, not a universal purity specification.

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Hydroperoxyl radical Lewis Structure

Hydroperoxyl radical Lewis Structure