Hydrogen sulfide Lewis Structure

Hydrogen sulfide Lewis Structure: H₂S Lewis Structure, bent Geometry, sp3 Hybridization & Polarity

Hydrogen sulfide Key Facts

The Hydrogen sulfide Lewis structure is 2 S–H single bond; the central S has 4 electron domains (2 lone pairs), giving a tetrahedral electron-domain arrangement and a bent molecular geometry with a ≈104.5° bond angle. S is best described as sp3-hybridized, and Hydrogen sulfide is polar because the bent shape (and/or unequal terminal atoms) prevents cancellation of the bond dipoles.

Figure 1: Lewis Structure of Hydrogen sulfide (H₂S)

Chemical Formula	H₂S
CAS Number	7783-06-4
Total Valence Electrons	8
Lewis Structure	2 S–H single bond
Electron-Domain Geometry	tetrahedral
Molecular Geometry	bent
Hybridization Model	sp3 (central S)
Bond Angle	≈104.5°
Polarity	Polar molecule

PubChem (CID 402) and NIST list Hydrogen sulfide as H ₂S with CAS 7783-06-4; molecular weight ≈ 34.08 g/mol. View CAS 7783-06-4 dictionary details on Guidechem →

Applications of Hydrogen sulfide (CAS 7783-06-4)

As a hydride of S, Hydrogen sulfide is typically a strong reducing agent, a potential fuel component, or a precursor in inorganic and organometallic synthesis. Many pnictogen/sulfur hydrides are toxic, foul-smelling and pyrophoric or flammable, and are handled with appropriate ventilation and inert-atmosphere technique.

Reducing Agent Electron-rich hydrides reduce metal centers and functional groups in synthesis.

Precursor / Feedstock Source of S in the preparation of derivatives and doped materials.

Handling Often toxic/flammable/pyrophoric; inert atmosphere and active ventilation required.

Procurement Note "Hydrogen sulfide" 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 7783-06-4 as the primary identifier when screening suppliers; always confirm regional availability and safety documentation (SDS).

Step 1 - Valence Electrons & Central Atom

To draw the Hydrogen sulfide Lewis structure we first count the total valence electrons. H₂S contains 2×1 (H) + 6 (S); the net charge of 0 gives a total of 8 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 = 2×1 (H) + 6 (S) = 8 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: 2 S–H single bond; 2 lone pairs on S.

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

S–H ×2

S: 2 lone pairs, 2 bonding domains

2 bonding domains + 2 lone pairs = 4 electron domains

Octet Rule: Why S Has Eight Electrons S forms 2 bond(s) and retains 4 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 2 of these domains are lone pair(s) — and lone pairs repel more strongly than bonding pairs — the observed molecular geometry is bent; the S bond angle is set to ≈104.5° 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 2 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 (2 bonding + 2 lone pair).

Formal-charge check

Formal charge on central S = V − N − ½B = 6 − 4 − ½×4 = 2. The nonzero formal charge is distributed by resonance / charge separation; the drawn structure is the lowest-energy 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 Hydrogen sulfide Polar or Nonpolar?

Hydrogen sulfide is polar. The bent 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 Hydrogen sulfide the bent 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
Hydrogen sulfide	H₂S	S	4	bent	Polar
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 8 valence electrons of H₂S, draw the Lewis structure and confirm the central S atom is sp3-hybridized with bent 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 Hydrogen sulfide (CAS 7783-06-4)? Browse Supplier on Guidechem →

FAQs

Is H₂S polar or nonpolar?

Hydrogen sulfide is polar. Its bent geometry (and/or unequal terminal atoms) stops the bond dipoles from cancelling.

What is the Lewis structure of Hydrogen sulfide?

2 S–H single bond; 2 lone pairs on S. It uses all 8 valence electrons and the preferred structure carries a formal charge of 2 on the central atom.

What is the bond angle in Hydrogen sulfide?

The S angle is about ≈104.5°. Lone-pair repulsion compresses the angle from the ideal tetrahedral value.

What is the hybridization of S in Hydrogen sulfide?

The conventional model is sp3. Hydrogen sulfide has 4 electron domains around the central S.

What is the CAS number of Hydrogen sulfide?

The CAS number is 7783-06-4. PubChem (CID 402) and NIST identify this with H₂S; use it to locate suppliers and database records.

References

PubChem CID 402, Hydrogen sulfide. Molecular formula, CAS number, molecular weight and chemical identity.
NIST Chemistry WebBook, SRD 69, Hydrogen sulfide. 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 Hydrogen sulfide (CAS 7783-06-4).

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 7783-06-4 identifies the substance, not a universal purity specification.

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Hydrogen sulfide Lewis Structure