Iodine dioxide Lewis Structure

Iodine dioxide Lewis Structure: IO₂ Lewis Structure, trigonal pyramidal Geometry, sp3 Hybridization & Polarity

Iodine dioxide Key Facts

The Iodine dioxide Lewis structure is I–O double bond, I–O double bond and I–H single bond; the central I has 4 electron domains (1 lone pair), giving a tetrahedral electron-domain arrangement and a trigonal pyramidal molecular geometry with a ≈107° bond angle. I is best described as sp3-hybridized, and Iodine dioxide is polar because the trigonal pyramidal shape (and/or unequal terminal atoms) prevents cancellation of the bond dipoles.

Figure 1: Lewis Structure of Iodine dioxide (IO₂)

Chemical Formula	IO2
CAS Number	27341-40-4
Total Valence Electrons	19
Lewis Structure	I–O double bond, I–O double bond and I–H single bond
Electron-Domain Geometry	tetrahedral
Molecular Geometry	trigonal pyramidal
Hybridization Model	sp3 (central I)
Bond Angle	≈107°
Polarity	Polar molecule

PubChem and NIST list Iodine dioxide as IO ₂ with CAS 27341-40-4; molecular weight ≈ None g/mol. View CAS 27341-40-4 dictionary details on Guidechem →

Applications of Iodine dioxide (CAS 27341-40-4)

Iodine dioxide 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.

Step 1 - Valence Electrons & Central Atom

To draw the Iodine dioxide Lewis structure we first count the total valence electrons. IO₂ contains 7 (I) + 2×6 (O); the net charge of 0 gives a total of 19 valence electrons to place.

The central atom is I. 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).

Step 2 - Lewis Structure & Electron Distribution

Place I 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: I–O double bond, I–O double bond and I–H single bond; one lone pair on I.

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

This species is best represented by resonance structures; the π bonding is delocalized over the equivalent terminal atom(s), so all I–terminals bonds are equivalent in the resonance hybrid.

Step 3 - VSEPR Theory & Geometry

VSEPR theory states that the 4 electron domains around I arrange to minimize mutual repulsion, giving an tetrahedral 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 trigonal pyramidal; the I bond angle is set to ≈107° rather than the ideal value for the electron-domain geometry.

Hybridization & Formal Charge

In the conventional localized-bond model, I uses sp3 hybrid orbitals to form the 4 equivalent electron-domain directions (3 bonding + 1 lone pair).

Is Iodine dioxide Polar or Nonpolar?

Iodine dioxide is polar. The trigonal pyramidal 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.

This polarity profile underpins its behavior as a solvent, reactant or process intermediate; when sourcing, specify grade and container compatibility.

Structural Comparison Table

FAQs

References