Sodium azide Lewis Structure

Sodium azide Lewis Structure: N₃Na Lewis Structure, linear Geometry, sp Hybridization & Polarity

Sodium azide Key Facts

The Sodium azide Lewis structure is N–N double bond and N–N double bond; the central N has 2 electron domains (0 lone pairs), giving a linear electron-domain arrangement and a linear molecular geometry with a 180° bond angle. N is best described as sp-hybridized, and Sodium azide is nonpolar because the bond dipoles cancel by molecular symmetry.

Figure 1: Lewis Structure of Sodium azide (N₃Na)

Chemical Formula	N₃Na
CAS Number	26628-22-8
Total Valence Electrons	16
Lewis Structure	N–N double bond and N–N double bond
Electron-Domain Geometry	linear
Molecular Geometry	linear
Hybridization Model	sp (central N)
Bond Angle	180°
Polarity	Nonpolar molecule

PubChem (CID 33557) and NIST list Sodium azide as N ₃Na with CAS 26628-22-8; molecular weight ≈ 65.010 g/mol. View CAS 26628-22-8 dictionary details on Guidechem →

Applications of Sodium azide (CAS 26628-22-8)

Sodium azide 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 "Sodium azide" 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 26628-22-8 as the primary identifier when screening suppliers; always confirm regional availability and safety documentation (SDS).

Step 1 - Valence Electrons & Central Atom

To draw the Sodium azide Lewis structure we first count the total valence electrons. N₃Na contains 3×5 (N) + 1 (Na); the net charge of 0 gives a total of 16 valence electrons to place.

The central atom is N. 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 = 3×5 (N) + 1 (Na) = 16 electrons.

Step 2 - Lewis Structure & Electron Distribution

Place N 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: N–N double bond and N–N double bond; no lone pairs on N.

Counting bonding and nonbonding electrons around N 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 N–terminals bonds are equivalent in the resonance hybrid.

N=N N=N

N: 0 lone pairs, 2 bonding domains

2 bonding domains + 0 lone pairs = 2 electron domains

Octet Rule: Why N Has Eight Electrons N forms 2 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 2 electron domains around N arrange to minimize mutual repulsion, giving an linear 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 linear; the N bond angle is set to 180° 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 N, 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, N uses sp hybrid orbitals to form the 2 equivalent electron-domain directions (2 bonding + 0 lone pair).

Formal-charge check

Formal charge on central N = V − N − ½B = 5 − 0 − 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: sp is a compact model for the 2 electron-domain directions around N; full quantum-chemical treatments use molecular orbitals.

Is Sodium azide Polar or Nonpolar?

Sodium azide is nonpolar. Although individual N–terminal bonds are polar when the atoms differ in electronegativity, the linear 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. Sodium azide shows the opposite: identical bond dipoles arranged with linear 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
Sodium azide	N₃Na	N	2	linear	Nonpolar
Ammonia	H₃N	N	4	trigonal pyramidal	Polar
Ammonium	H₄N	N	4	tetrahedral	Nonpolar
Hydrazine	H₄N₂	N	4	trigonal pyramidal	Polar
Nitrogen	N₂	N	2	linear (diatomic)	Nonpolar
Nitric oxide	NO	N	3	linear (diatomic)	Polar

Practice question Starting from the 16 valence electrons of N₃Na, draw the Lewis structure and confirm the central N atom is sp-hybridized with linear 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 Sodium azide (CAS 26628-22-8)? Browse Supplier on Guidechem →

FAQs

Is N₃Na polar or nonpolar?

Sodium azide is nonpolar. Its linear symmetry cancels the bond dipoles exactly.

What is the Lewis structure of Sodium azide?

N–N double bond and N–N double bond; no lone pairs on N. It uses all 16 valence electrons and the preferred structure carries a formal charge of 1 on the central atom.

What is the bond angle in Sodium azide?

The N angle is about 180°. Lone-pair repulsion compresses the angle from the ideal linear value.

What is the hybridization of N in Sodium azide?

The conventional model is sp. Sodium azide has 2 electron domains around the central N.

What is the CAS number of Sodium azide?

The CAS number is 26628-22-8. PubChem (CID 33557) and NIST identify this with N₃Na; use it to locate suppliers and database records.

References

PubChem CID 33557, Sodium azide. Molecular formula, CAS number, molecular weight and chemical identity.
NIST Chemistry WebBook, SRD 69, Sodium azide. 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 Sodium azide (CAS 26628-22-8).

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 26628-22-8 identifies the substance, not a universal purity specification.

Make Guideview Preferred Source on Google

Sodium azide Lewis Structure

Sodium azide Lewis Structure