Silicon carbide Lewis Structure

Silicon carbide Lewis Structure: CSi Lewis Structure, linear (diatomic) Geometry, sp Hybridization & Polarity

Silicon carbide Key Facts

The Silicon carbide Lewis structure is a linear diatomic with a polar bond between its two atoms; because the two atoms differ in electronegativity, Silicon carbide is polar.

Figure 1: Lewis Structure of Silicon carbide (CSi)

Chemical Formula	CSi
CAS Number	409-21-2
Total Valence Electrons	8
Lewis Structure	linear diatomic molecule with one triple bond
Electron-Domain Geometry	linear
Molecular Geometry	linear (diatomic)
Hybridization Model	sp
Bond Angle	180°
Polarity	Polar molecule

PubChem (CID 9863) and NIST list Silicon carbide as CSi with CAS 409-21-2; molecular weight ≈ 40.096 g/mol. View CAS 409-21-2 dictionary details on Guidechem →

Applications of Silicon carbide (CAS 409-21-2)

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 "Silicon carbide" 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 409-21-2 as the primary identifier when screening suppliers; always confirm regional availability and safety documentation (SDS).

Step 1 - Valence Electrons & Central Atom

To draw the Silicon carbide Lewis structure we first count the total valence electrons. CSi contains 4 (C) + 4 (Si); the net charge of 0 gives a total of 8 valence electrons to place.

The central atom is C. 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) + 4 (Si) = 8 electrons.

Step 2 - Lewis Structure & Electron Distribution

Place C 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: linear diatomic molecule with one triple bond; 1 lone pair(s) on C.

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

C–Si

C: 1 lone pair, 1 bonding domain

1 bonding domains + 1 lone pairs = 2 electron domains

Octet & Diradical Note In a simple Lewis drawing each atom of this homonuclear diatomic carries lone pairs; species such as O₂ are more accurately described by molecular-orbital theory (paramagnetism arises from unpaired electrons in π* orbitals).

Step 3 - VSEPR Theory & Geometry

VSEPR theory states that the 2 electron domains around C 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 linear (diatomic); the C 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 1 lone pair(s) on C, 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, C uses sp hybrid orbitals to form the 2 equivalent electron-domain directions (1 bonding + 1 lone pair).

Formal-charge check

Formal charge on central C = V − N − ½B = 4 − 2 − ½×6 = -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 C; full quantum-chemical treatments use molecular orbitals.

Is Silicon carbide Polar or Nonpolar?

Silicon carbide is polar. The linear (diatomic) 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 Silicon carbide the linear (diatomic) 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
Silicon carbide	CSi	C	2	linear (diatomic)	Polar
Carbon dioxide	CO₂	C	2	linear	Nonpolar
Carbon monoxide	CO	C	2	linear (diatomic)	Polar
Carbon disulfide	CS₂	C	2	linear	Nonpolar
Methane	CH₄	C	4	tetrahedral	Nonpolar
Ethane	C₂H₆	C	4	tetrahedral	Nonpolar

Practice question Starting from the 8 valence electrons of CSi, draw the Lewis structure and confirm the central C atom is sp-hybridized with linear (diatomic) 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 Silicon carbide (CAS 409-21-2)? Browse Supplier on Guidechem →

FAQs

Is CSi polar or nonpolar?

Silicon carbide is polar. Its linear (diatomic) geometry (and/or unequal terminal atoms) stops the bond dipoles from cancelling.

What is the Lewis structure of Silicon carbide?

linear diatomic molecule with one triple bond; 1 lone pair(s) on C. It uses all 8 valence electrons and the preferred structure carries a formal charge of -1 on the central atom.

What is the bond angle in Silicon carbide?

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

What is the hybridization of C in Silicon carbide?

The conventional model is sp. Silicon carbide has 2 electron domains around the central C.

What is the CAS number of Silicon carbide?

The CAS number is 409-21-2. PubChem (CID 9863) and NIST identify this with CSi; use it to locate suppliers and database records.

References

PubChem CID 9863, Silicon carbide. Molecular formula, CAS number, molecular weight and chemical identity.
NIST Chemistry WebBook, SRD 69, Silicon carbide. 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 Silicon carbide (CAS 409-21-2).

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 409-21-2 identifies the substance, not a universal purity specification.

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Silicon carbide Lewis Structure