Brilliant Blue FCF Lewis Structure

Brilliant Blue FCF Lewis Structure: C₃₇H₃₄N₂Na₂O₉S₃ Lewis Structure, tetrahedral Geometry, sp3 Hybridization & Polarity

Brilliant Blue FCF Key Facts

The Brilliant Blue FCF Lewis structure is S–C 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 Brilliant Blue FCF is polar because the tetrahedral shape (and/or unequal terminal atoms) prevents cancellation of the bond dipoles.

Figure 1: Lewis Structure of Brilliant Blue FCF (C₃₇H₃₄N₂Na₂O₉S₃)

Chemical Formula	C₃₇H₃₄N₂Na₂O₉S₃
CAS Number	3844-45-9
Total Valence Electrons	266
Lewis Structure	S–C 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	Polar molecule

PubChem (CID 19700) and NIST list Brilliant Blue FCF as C ₃₇H ₃₄N ₂Na ₂O ₉S ₃ with CAS 3844-45-9; molecular weight ≈ 792.9 g/mol. View CAS 3844-45-9 dictionary details on Guidechem →

Applications of Brilliant Blue FCF (CAS 3844-45-9)

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 "Brilliant Blue FCF" 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 3844-45-9 as the primary identifier when screening suppliers; always confirm regional availability and safety documentation (SDS).

Step 1 - Valence Electrons & Central Atom

To draw the Brilliant Blue FCF Lewis structure we first count the total valence electrons. C₃₇H₃₄N₂Na₂O₉S₃ contains 37×4 (C) + 34×1 (H) + 2×5 (N) + 2×1 (Na) + 9×6 (O) + 3×6 (S); the net charge of 0 gives a total of 266 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 = 37×4 (C) + 34×1 (H) + 2×5 (N) + 2×1 (Na) + 9×6 (O) + 3×6 (S) = 266 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–C 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.

S–C 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 Brilliant Blue FCF Polar or Nonpolar?

Brilliant Blue FCF is polar. The tetrahedral 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 Brilliant Blue FCF the tetrahedral 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
Brilliant Blue FCF	C₃₇H₃₄N₂Na₂O₉S₃	S	4	tetrahedral	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 266 valence electrons of C₃₇H₃₄N₂Na₂O₉S₃, 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 Brilliant Blue FCF (CAS 3844-45-9)? Browse Supplier on Guidechem →

FAQs

Is C₃₇H₃₄N₂Na₂O₉S₃ polar or nonpolar?

Brilliant Blue FCF is polar. Its tetrahedral geometry (and/or unequal terminal atoms) stops the bond dipoles from cancelling.

What is the Lewis structure of Brilliant Blue FCF?

S–C single bond, S–O double bond, S–O double bond and S–O single bond; no lone pairs on S. It uses all 266 valence electrons and the preferred structure carries zero formal charge on the central atom.

What is the bond angle in Brilliant Blue FCF?

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 Brilliant Blue FCF?

The conventional model is sp3. Brilliant Blue FCF has 4 electron domains around the central S.

What is the CAS number of Brilliant Blue FCF?

The CAS number is 3844-45-9. PubChem (CID 19700) and NIST identify this with C₃₇H₃₄N₂Na₂O₉S₃; use it to locate suppliers and database records.

References

PubChem CID 19700, Brilliant Blue FCF. Molecular formula, CAS number, molecular weight and chemical identity.
NIST Chemistry WebBook, SRD 69, Brilliant Blue FCF. 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 Brilliant Blue FCF (CAS 3844-45-9).

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 3844-45-9 identifies the substance, not a universal purity specification.

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Brilliant Blue FCF Lewis Structure