Iodine heptafluoride Lewis Structure

Iodine heptafluoride Lewis Structure: F₇I Lewis Structure, pentagonal bipyramidal Geometry, sp3d3 Hybridization & Polarity

Iodine heptafluoride Key Facts

The Iodine heptafluoride Lewis structure is I–F single bond, I–F single bond, I–F single bond, I–F single bond, I–F single bond, I–F single bond and I–F single bond; the central I has 7 electron domains (0 lone pairs), giving a pentagonal bipyramidal electron-domain arrangement and a pentagonal bipyramidal molecular geometry with a 90° / 72° bond angle. I is best described as sp3d3-hybridized, and Iodine heptafluoride is nonpolar because the bond dipoles cancel by molecular symmetry.

Figure 1: Lewis Structure of Iodine heptafluoride (F₇I)

Chemical Formula	F₇I
CAS Number	16921-38-5
Total Valence Electrons	56
Lewis Structure	I–F single bond, I–F single bond, I–F single bond, I–F single bond, I–F single bond, I–F single bond and I–F single bond
Electron-Domain Geometry	pentagonal bipyramidal
Molecular Geometry	pentagonal bipyramidal
Hybridization Model	sp3d3 (central I)
Bond Angle	90° / 72°
Polarity	Nonpolar molecule

PubChem (CID 85645) and NIST list Iodine heptafluoride as F ₇I with CAS 16921-38-5; molecular weight ≈ 259.8933 g/mol. View CAS 16921-38-5 dictionary details on Guidechem →

Applications of Iodine heptafluoride (CAS 16921-38-5)

Interhalogen fluorides such as Iodine heptafluoride are exceptionally vigorous fluorinating and oxidizing agents. They are employed in uranium processing, in the fluorination of metals, ceramics and polymers, and as rocket oxidizers. Their reactivity with water and organics is extreme, so they are handled only in passivated, dry systems.

Fluorinating Agent Converts metals and refractory materials to volatile fluorides for separation and processing.

Oxidizer High-energy oxidizer role in specialized propulsion and synthesis.

Handling Extreme moisture/organics sensitivity; strictly anhydrous, passivated equipment.

Procurement Note "Iodine heptafluoride" 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 16921-38-5 as the primary identifier when screening suppliers; always confirm regional availability and safety documentation (SDS).

Step 1 - Valence Electrons & Central Atom

To draw the Iodine heptafluoride Lewis structure we first count the total valence electrons. F₇I contains 7×7 (F) + 7 (I); the net charge of 0 gives a total of 56 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 = 7×7 (F) + 7 (I) = 56 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–F single bond, I–F single bond, I–F single bond, I–F single bond, I–F single bond, I–F single bond and I–F single bond; no lone pairs on I.

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

I–F I–F I–F I–F I–F I–F I–F

I: 0 lone pairs, 7 bonding domains

7 bonding domains + 0 lone pairs = 7 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 pentagonal bipyramidal arrangement with 7 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 7 electron domains around I arrange to minimize mutual repulsion, giving an pentagonal bipyramidal 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 pentagonal bipyramidal; the I bond angle is set to 90° / 72° 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 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 sp3d3 hybrid orbitals to form the 7 equivalent electron-domain directions (7 bonding + 0 lone pair).

Formal-charge check

Formal charge on central I = V − N − ½B = 7 − 0 − ½×14 = 0. The preferred Lewis structure carries zero formal charge on the central atom (and on the terminals), so it is the dominant contributor.

Modeling Note Modeling Note: sp3d3 / sp3d3 hybridization is a convenient localized-bond teaching model. Modern quantum-chemical descriptions of hypervalent Iodine heptafluoride use molecular orbitals and do not require populated d orbitals as the primary bonding picture.

Is Iodine heptafluoride Polar or Nonpolar?

Iodine heptafluoride is nonpolar. Although individual I–terminal bonds are polar when the atoms differ in electronegativity, the pentagonal bipyramidal 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. Iodine heptafluoride shows the opposite: identical bond dipoles arranged with pentagonal bipyramidal 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
Iodine heptafluoride	F₇I	I	7	pentagonal bipyramidal	Nonpolar
Iodine trifluoride	IF₃	I	5	T-shaped	Polar
Iodine pentafluoride	IF₅	I	6	square pyramidal	Polar
Iodine	I₂	I	4	linear (diatomic)	Nonpolar
Hydrogen iodide	HI	I	4	linear (diatomic)	Polar

Practice question Starting from the 56 valence electrons of F₇I, draw the Lewis structure and confirm the central I atom is sp3d3-hybridized with pentagonal bipyramidal 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 Iodine heptafluoride (CAS 16921-38-5)? Browse Supplier on Guidechem →

FAQs

Is F₇I polar or nonpolar?

Iodine heptafluoride is nonpolar. Its pentagonal bipyramidal symmetry cancels the bond dipoles exactly.

What is the Lewis structure of Iodine heptafluoride?

I–F single bond, I–F single bond, I–F single bond, I–F single bond, I–F single bond, I–F single bond and I–F single bond; no lone pairs on I. It uses all 56 valence electrons and the preferred structure carries zero formal charge on the central atom.

What is the bond angle in Iodine heptafluoride?

The I angle is about 90° / 72°. Lone-pair repulsion compresses the angle from the ideal pentagonal bipyramidal value.

What is the hybridization of I in Iodine heptafluoride?

The conventional model is sp3d3. Iodine heptafluoride has 7 electron domains around the central I.

What is the CAS number of Iodine heptafluoride?

The CAS number is 16921-38-5. PubChem (CID 85645) and NIST identify this with F₇I; use it to locate suppliers and database records.

References

PubChem CID 85645, Iodine heptafluoride. Molecular formula, CAS number, molecular weight and chemical identity.
NIST Chemistry WebBook, SRD 69, Iodine heptafluoride. 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 Iodine heptafluoride (CAS 16921-38-5).

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 16921-38-5 identifies the substance, not a universal purity specification.

Make Guideview Preferred Source on Google

Iodine heptafluoride Lewis Structure

Iodine heptafluoride Lewis Structure