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Barium sulfate Lewis Structure

Barium sulfate Lewis structure (BaO4S). S–O single bond, S–O double bond, S–O double bond and S–O single bond. It shows a tetrahedral shape, sp3 hybridization on S, 109.5° bond angles. Includes a comparison table and FAQs. Isabel3 MIN READSeptember 30, 2026

Barium sulfate Lewis Structure: BaO4S Lewis Structure, tetrahedral Geometry, sp3 Hybridization & Polarity

Barium sulfate Lewis structure Cover

Barium sulfate Key Facts

The Barium sulfate Lewis structure is S–O single bond, S–O double bond, S–O double bond and S–O single bond; the central S has 4 electron domains (0 lone pairs), giving a tetrahedral electron-domain arrangement and a tetrahedral molecular geometry with a 109.5° bond angle. S is best described as sp3-hybridized, and Barium sulfate is nonpolar because the bond dipoles cancel by molecular symmetry.

Barium sulfate Lewis Structure Figure 1: Lewis Structure of Barium sulfate (BaO4S)
Chemical Formula BaO4S
CAS Number 7727-43-7
Total Valence Electrons 32
Lewis Structure S–O single bond, S–O double bond, S–O double bond and S–O single bond
Electron-Domain Geometry tetrahedral
Molecular Geometry tetrahedral
Hybridization Model sp3 (central S)
Bond Angle 109.5°
Polarity Nonpolar molecule
PubChem (CID 24414) and NIST list Barium sulfate as BaO 4S with CAS 7727-43-7; molecular weight ≈ 233.39 g/mol. View CAS 7727-43-7 dictionary details on Guidechem →

Applications of Barium sulfate (CAS 7727-43-7)

The S oxide Barium sulfate is a key industrial intermediate. Nonmetal oxides such as SO3 and P4O10 are acid anhydrides for sulfuric and phosphoric acid manufacture, while metal/semimetal oxides are ceramics, refractories, catalysts and pigment precursors.

Acid Anhydride / Intermediate Gateway to the corresponding oxoacid and its salts (fertilizers, detergents).
Materials & Catalysis Oxide ceramics, refractories, catalysts and pigment feedstocks.
Process Gas / Reagent Oxidizing or reactive reagent in inorganic and environmental processing.
Procurement Note "Barium sulfate" 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 7727-43-7 as the primary identifier when screening suppliers; always confirm regional availability and safety documentation (SDS).

Step 1 - Valence Electrons & Central Atom

To draw the Barium sulfate Lewis structure we first count the total valence electrons. BaO4S contains 2 (Ba) + 4×6 (O) + 6 (S); the net charge of 0 gives a total of 32 valence electrons to place.

The central atom is S. 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 = 2 (Ba) + 4×6 (O) + 6 (S) = 32 electrons.

Step 2 - Lewis Structure & Electron Distribution

Place S 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: S–O single bond, S–O double bond, S–O double bond and S–O single bond; no lone pairs on S.

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

S–O S=O S=O S–O
S: 0 lone pairs, 4 bonding domains
4 bonding domains + 0 lone pairs = 4 electron domains
Octet Rule: Why S Has Eight Electrons S forms 4 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 4 electron domains around S arrange to minimize mutual repulsion, giving an tetrahedral 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 tetrahedral; the S bond angle is set to 109.5° 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 S, 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, S uses sp3 hybrid orbitals to form the 4 equivalent electron-domain directions (4 bonding + 0 lone pair).

Formal-charge check

Formal charge on central S = V − N − ½B = 6 − 0 − ½×12 = 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: sp3 is a compact model for the 4 electron-domain directions around S; full quantum-chemical treatments use molecular orbitals.

Is Barium sulfate Polar or Nonpolar?

Barium sulfate is nonpolar. Although individual S–terminal bonds are polar when the atoms differ in electronegativity, the tetrahedral 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. Barium sulfate shows the opposite: identical bond dipoles arranged with tetrahedral 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
Barium sulfate BaO4S S 4 tetrahedral Nonpolar
Sulfur dioxide SO2 S 3 bent Polar
Sulfur trioxide O3S S 3 trigonal planar Nonpolar
Sulfur hexafluoride F6S S 6 octahedral Nonpolar
Sulfur tetrafluoride F4S S 5 seesaw Polar
Sulfate O4S S 4 tetrahedral Nonpolar
Practice question Starting from the 32 valence electrons of BaO4S, draw the Lewis structure and confirm the central S atom is sp3-hybridized with tetrahedral 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 Barium sulfate (CAS 7727-43-7)? Browse Supplier on Guidechem →

FAQs

Is BaO4S polar or nonpolar?

Barium sulfate is nonpolar. Its tetrahedral symmetry cancels the bond dipoles exactly.

What is the Lewis structure of Barium sulfate?

S–O single bond, S–O double bond, S–O double bond and S–O single bond; no lone pairs on S. It uses all 32 valence electrons and the preferred structure carries zero formal charge on the central atom.

What is the bond angle in Barium sulfate?

The S angle is about 109.5°. Lone-pair repulsion compresses the angle from the ideal tetrahedral value.

What is the hybridization of S in Barium sulfate?

The conventional model is sp3. Barium sulfate has 4 electron domains around the central S.

What is the CAS number of Barium sulfate?

The CAS number is 7727-43-7. PubChem (CID 24414) and NIST identify this with BaO4S; use it to locate suppliers and database records.

References

  1. PubChem CID 24414, Barium sulfate. Molecular formula, CAS number, molecular weight and chemical identity.
  2. NIST Chemistry WebBook, SRD 69, Barium sulfate. Formula, CAS Registry Number and thermochemical / spectroscopic data.
  3. IUPAC Gold Book. Definitions for "lone pair", "VSEPR", "hybridization" and "formal charge".
  4. Atkins, P. & de Paula, J., Physical Chemistry. VSEPR, molecular geometry and dipole moments.
  5. Guidechem supplier & dictionary records. Commercial sourcing and CAS-linked property pages for Barium sulfate (CAS 7727-43-7).

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 7727-43-7 identifies the substance, not a universal purity specification.

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