Tetrachloroiodate(III) ion Lewis Structure

Tetrachloroiodate(III) ion Lewis Structure: ICl₄ Lewis Structure, square planar Geometry, sp3d2 Hybridization & Polarity

Tetrachloroiodate(III) ion Key Facts

The Tetrachloroiodate(III) ion Lewis structure is I–Cl single bond, I–Cl single bond, I–Cl single bond and I–Cl single bond; the central I has 6 electron domains (2 lone pairs), giving a octahedral electron-domain arrangement and a square planar molecular geometry with a 90° bond angle. I is best described as sp3d2-hybridized, and Tetrachloroiodate(III) ion is nonpolar because the bond dipoles cancel by molecular symmetry.

Figure 1: Lewis Structure of Tetrachloroiodate(III) ion (ICl₄)

Chemical Formula	ICl₄
CAS Number	14351-80-5
Net Charge	-1
Total Valence Electrons	36
Lewis Structure	I–Cl single bond, I–Cl single bond, I–Cl single bond and I–Cl single bond
Electron-Domain Geometry	octahedral
Molecular Geometry	square planar
Hybridization Model	sp3d2 (central I)
Bond Angle	90°
Polarity	Nonpolar molecule

PubChem and NIST list Tetrachloroiodate(III) ion as ICl ₄ with CAS 14351-80-5; molecular weight ≈ None g/mol. View CAS 14351-80-5 dictionary details on Guidechem →

Applications of Tetrachloroiodate(III) ion (CAS 14351-80-5)

In aqueous and process chemistry, ICl₄ exists as the anion Tetrachloroiodate(III) ion ion. It is encountered as a counterion and a controlled source of I in salts, buffers, electrochemistry and analytical protocols, and as a reactant in syntheses that require a defined equivalent of I-containing material.

Ion Source / Counterion Supplied as salts and solutions; specify hydration, counter-cation and concentration.

Analytical & Electrochemical Used in titrations, plating baths and ionic-strength control where the ion is the active species.

Synthesis Reagent A controlled source of I in precipitation, complexation and redox procedures.

Procurement Note "Tetrachloroiodate(III) ion" 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 14351-80-5 as the primary identifier when screening suppliers; always confirm regional availability and safety documentation (SDS).

Step 1 - Valence Electrons & Central Atom

To draw the Tetrachloroiodate(III) ion Lewis structure we first count the total valence electrons. ICl₄ contains 7 (I) + 4×7 (Cl) − 1 (net anion); the net charge of -1 gives a total of 36 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).

Valence-electron count

Total valence electrons = 7 (I) + 4×7 (Cl) − 1 (net anion) = 36 electrons.

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–Cl single bond, I–Cl single bond, I–Cl single bond and I–Cl single bond; 2 lone pairs on I.

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

I–Cl I–Cl I–Cl I–Cl

I: 2 lone pairs, 4 bonding domains

4 bonding domains + 2 lone pairs = 6 electron domains

Expanded Octet: d-Orbital Participation Central I belongs to period 3 or below, so it can accommodate more than eight electrons: low-lying d orbitals become available and the square planar arrangement with 6 domains reflects this expanded valence shell. The octet rule alone does not apply to such hypervalent species.

Step 3 - VSEPR Theory & Geometry

VSEPR theory states that the 6 electron domains around I arrange to minimize mutual repulsion, giving an octahedral 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 square planar; the I bond angle is set to 90° 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 I, 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, I uses sp3d2 hybrid orbitals to form the 6 equivalent electron-domain directions (4 bonding + 2 lone pair).

Formal-charge check

Formal charge on central I = V − N − ½B = 7 − 4 − ½×8 = -1. The nonzero formal charge is distributed by resonance / charge separation; the drawn structure is the lowest-energy contributor.

Modeling Note Modeling Note: sp3d2 / sp3d2 hybridization is a convenient localized-bond teaching model. Modern quantum-chemical descriptions of hypervalent Tetrachloroiodate(III) ion use molecular orbitals and do not require populated d orbitals as the primary bonding picture.

Is Tetrachloroiodate(III) ion Polar or Nonpolar?

Tetrachloroiodate(III) ion is nonpolar. Although individual I–terminal bonds are polar when the atoms differ in electronegativity, the square planar geometry makes their vector sum zero, so there is no net molecular dipole.

Expert Quote — Structural Chemistry Perspective

A common misconception is that polar bonds guarantee a polar molecule. Tetrachloroiodate(III) ion shows the opposite: identical bond dipoles arranged with square planar symmetry cancel exactly, yielding a nonpolar species.

Interpretation consistent with standard VSEPR / molecular-geometry references.

Its nonpolar character governs solvation and intermolecular behavior; specify grade and handling when sourcing.

Structural Comparison Table

Species	Formula	Central Atom	Electron Domains	Molecular Geometry	Polarity
Tetrachloroiodate(III) ion	ICl₄	I	6	square planar	Nonpolar
Iodine trifluoride	IF₃	I	5	T-shaped	Polar
Iodine pentafluoride	IF₅	I	6	square pyramidal	Polar
Iodine heptafluoride	IF₇	I	7	pentagonal bipyramidal	Nonpolar
Iodine	I₂	I	4	linear (diatomic)	Nonpolar
Hydrogen iodide	HI	I	4	linear (diatomic)	Polar

Practice question Starting from the 36 valence electrons of ICl₄, draw the Lewis structure and confirm the central I atom is sp3d2-hybridized with square planar 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 Tetrachloroiodate(III) ion (CAS 14351-80-5)? Browse Supplier on Guidechem →

FAQs

Is ICl₄ polar or nonpolar?

Tetrachloroiodate(III) ion is nonpolar. Its square planar symmetry cancels the bond dipoles exactly.

What is the Lewis structure of Tetrachloroiodate(III) ion?

I–Cl single bond, I–Cl single bond, I–Cl single bond and I–Cl single bond; 2 lone pairs on I. It uses all 36 valence electrons and the preferred structure carries a formal charge of -1 on the central atom.

What is the bond angle in Tetrachloroiodate(III) ion?

The I angle is about 90°. Lone-pair repulsion compresses the angle from the ideal octahedral value.

What is the hybridization of I in Tetrachloroiodate(III) ion?

The conventional model is sp3d2. Tetrachloroiodate(III) ion has 6 electron domains around the central I.

What is the CAS number of Tetrachloroiodate(III) ion?

The CAS number is 14351-80-5. PubChem and NIST identify this with ICl₄; use it to locate suppliers and database records.

References

PubChem, Tetrachloroiodate(III) ion. Molecular formula, CAS number, molecular weight and chemical identity.
NIST Chemistry WebBook, SRD 69, Tetrachloroiodate(III) ion. 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 Tetrachloroiodate(III) ion (CAS 14351-80-5).

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 14351-80-5 identifies the substance, not a universal purity specification.

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Tetrachloroiodate(III) ion Lewis Structure

Tetrachloroiodate(III) ion Lewis Structure