Tin(II) bromide Lewis Structure

Tin(II) bromide Lewis Structure: Br₂Sn Lewis Structure, bent Geometry, sp2 Hybridization & Polarity

Tin(II) bromide Key Facts

The Tin(II) bromide Lewis structure is Sn–Br single bond and Sn–Br single bond; the central Sn has 3 electron domains (1 lone pair), giving a trigonal planar electron-domain arrangement and a bent molecular geometry with a ≈119° bond angle. Sn is best described as sp2-hybridized, and Tin(II) bromide is polar because the bent shape (and/or unequal terminal atoms) prevents cancellation of the bond dipoles.

Figure 1: Lewis Structure of Tin(II) bromide (Br₂Sn)

Chemical Formula	Br₂Sn
CAS Number	13465-43-5
Total Valence Electrons	18
Lewis Structure	Sn–Br single bond and Sn–Br single bond
Electron-Domain Geometry	trigonal planar
Molecular Geometry	bent
Hybridization Model	sp2 (central Sn)
Bond Angle	≈119°
Polarity	Polar molecule

PubChem (CID 66224) and NIST list Tin(II) bromide as Br ₂Sn with CAS 13465-43-5; molecular weight ≈ 278.52 g/mol. View CAS 13465-43-5 dictionary details on Guidechem →

Applications of Tin(II) bromide (CAS 13465-43-5)

Tin(II) bromide 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 "Tin(II) bromide" 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 13465-43-5 as the primary identifier when screening suppliers; always confirm regional availability and safety documentation (SDS).

Step 1 - Valence Electrons & Central Atom

To draw the Tin(II) bromide Lewis structure we first count the total valence electrons. Br₂Sn contains 2×7 (Br) + 4 (Sn); the net charge of 0 gives a total of 18 valence electrons to place.

The central atom is Sn. 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 = 2×7 (Br) + 4 (Sn) = 18 electrons.

Step 2 - Lewis Structure & Electron Distribution

Place Sn 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: Sn–Br single bond and Sn–Br single bond; one lone pair on Sn.

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

Sn–Br Sn–Br

Sn: 1 lone pair, 2 bonding domains

2 bonding domains + 1 lone pairs = 3 electron domains

Octet Rule: Why Sn Has Eight Electrons Sn forms 2 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 3 electron domains around Sn arrange to minimize mutual repulsion, giving an trigonal planar 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 bent; the Sn bond angle is set to ≈119° 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 Sn, 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, Sn uses sp2 hybrid orbitals to form the 3 equivalent electron-domain directions (2 bonding + 1 lone pair).

Formal-charge check

Formal charge on central Sn = V − N − ½B = 4 − 2 − ½×4 = 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: sp2 is a compact model for the 3 electron-domain directions around Sn; full quantum-chemical treatments use molecular orbitals.

Is Tin(II) bromide Polar or Nonpolar?

Tin(II) bromide 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 Tin(II) bromide 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
Tin(II) bromide	Br₂Sn	Sn	3	bent	Polar
Carbon dioxide	CO₂	C	2	linear	Nonpolar
Carbon monoxide	CO	C	2	linear (diatomic)	Polar
Carbon disulfide	CS₂	C	2	linear	Nonpolar

Practice question Starting from the 18 valence electrons of Br₂Sn, draw the Lewis structure and confirm the central Sn atom is sp2-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 Tin(II) bromide (CAS 13465-43-5)? Browse Supplier on Guidechem →

FAQs

Is Br₂Sn polar or nonpolar?

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

What is the Lewis structure of Tin(II) bromide?

Sn–Br single bond and Sn–Br single bond; one lone pair on Sn. It uses all 18 valence electrons and the preferred structure carries zero formal charge on the central atom.

What is the bond angle in Tin(II) bromide?

The Sn angle is about ≈119°. Lone-pair repulsion compresses the angle from the ideal trigonal planar value.

What is the hybridization of Sn in Tin(II) bromide?

The conventional model is sp2. Tin(II) bromide has 3 electron domains around the central Sn.

What is the CAS number of Tin(II) bromide?

The CAS number is 13465-43-5. PubChem (CID 66224) and NIST identify this with Br₂Sn; use it to locate suppliers and database records.

References

PubChem CID 66224, Tin(II) bromide. Molecular formula, CAS number, molecular weight and chemical identity.
NIST Chemistry WebBook, SRD 69, Tin(II) bromide. 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 Tin(II) bromide (CAS 13465-43-5).

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 13465-43-5 identifies the substance, not a universal purity specification.

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Tin(II) bromide Lewis Structure