Sodium cyanide Lewis Structure

Sodium cyanide Lewis Structure: CNNa Lewis Structure, see text Geometry, sp Hybridization & Polarity

Sodium cyanide Key Facts

The Sodium cyanide Lewis structure is N–C triple bond; the central N has 2 electron domains (1 lone pair), giving a linear electron-domain arrangement and a see text molecular geometry with a — bond angle. N is best described as sp-hybridized, and Sodium cyanide is polar because the see text shape (and/or unequal terminal atoms) prevents cancellation of the bond dipoles.

Figure 1: Lewis Structure of Sodium cyanide (CNNa)

Chemical Formula	CNNa
CAS Number	143-33-9
Total Valence Electrons	10
Lewis Structure	N–C triple bond
Electron-Domain Geometry	linear
Molecular Geometry	see text
Hybridization Model	sp (central N)
Bond Angle	—
Polarity	Polar molecule

PubChem (CID 8929) and NIST list Sodium cyanide as CNNa with CAS 143-33-9; molecular weight ≈ 49.007 g/mol. View CAS 143-33-9 dictionary details on Guidechem →

Applications of Sodium cyanide (CAS 143-33-9)

This organic compound is used as a solvent, intermediate or specialty reagent in fine-chemical, pharmaceutical and materials synthesis; specify grade and impurity profile when sourcing.

Solvent / Reagent Medium for reactions, extraction or formulation.

Intermediate Building block for downstream derivatives.

Specialty Use Targeted role in pharma/fragrance/materials.

Procurement Note "Sodium cyanide" 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 143-33-9 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 cyanide Lewis structure we first count the total valence electrons. CNNa contains 4 (C) + 5 (N) + 1 (Na); the net charge of 0 gives a total of 10 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 = 4 (C) + 5 (N) + 1 (Na) = 10 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–C triple bond; one lone pair on N.

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

N≡C

N: 1 lone pair, 1 bonding domain

1 bonding domains + 1 lone pairs = 2 electron domains

Octet Rule: Why N Has Eight Electrons N forms 1 bond(s) and retains 2 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 1 of these domains are lone pair(s) — and lone pairs repel more strongly than bonding pairs — the observed molecular geometry is see text; the N bond angle is set to — 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 1 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 (1 bonding + 1 lone pair).

Formal-charge check

Formal charge on central N = V − N − ½B = 5 − 2 − ½×6 = 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: sp is a compact model for the 2 electron-domain directions around N; full quantum-chemical treatments use molecular orbitals.

Is Sodium cyanide Polar or Nonpolar?

Sodium cyanide is polar. The see text 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 Sodium cyanide the see text 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
Sodium cyanide	CNNa	N	2	see text	Polar
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 10 valence electrons of CNNa, draw the Lewis structure and confirm the central N atom is sp-hybridized with see text 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 cyanide (CAS 143-33-9)? Browse Supplier on Guidechem →

FAQs

Is CNNa polar or nonpolar?

Sodium cyanide is polar. Its see text geometry (and/or unequal terminal atoms) stops the bond dipoles from cancelling.

What is the Lewis structure of Sodium cyanide?

N–C triple bond; one lone pair on N. It uses all 10 valence electrons and the preferred structure carries zero formal charge on the central atom.

What is the bond angle in Sodium cyanide?

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

What is the hybridization of N in Sodium cyanide?

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

What is the CAS number of Sodium cyanide?

The CAS number is 143-33-9. PubChem (CID 8929) and NIST identify this with CNNa; use it to locate suppliers and database records.

References

PubChem CID 8929, Sodium cyanide. Molecular formula, CAS number, molecular weight and chemical identity.
NIST Chemistry WebBook, SRD 69, Sodium cyanide. 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 cyanide (CAS 143-33-9).

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 143-33-9 identifies the substance, not a universal purity specification.

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Sodium cyanide Lewis Structure