Brilliant Blue FCF Polarity

Reviewed by: Guidechem Scientific Editorial Board

Standards: IUPAC & PubChem Guidelines | Updated: 2026

Is C₃₇H₃₄N₂Na₂O₉S₃ (Brilliant Blue FCF) Polar or Nonpolar? Molecular Polarity & Structure Analysis

C₃₇H₃₄N₂Na₂O₉S₃ (Brilliant Blue FCF) is ionic. It is not meaningfully described as "polar" or "nonpolar" at the level of a single molecule: the substance consists of separated ions, so charge separation and hydration — not a molecular dipole — govern how it behaves. The dipole value tabulated for a single ion pair is origin-dependent and is reported below only as a calculated reference number.

2D Lewis Structure of Brilliant Blue FCF (C37H34N2Na2O9S3)

Figure 1: 2D Lewis Structure (C ₃₇H ₃₄N ₂Na ₂O ₉S ₃; tetrahedral sulfur centre)

Polarity Parameters of C₃₇H₃₄N₂Na₂O₉S₃

CAS Registry Number	3844-45-9
Molecular Formula	C₃₇H₃₄N₂Na₂O₉S₃
Molecular Weight	792.9 g/mol
Valence Electrons	266
Lewis Structure Guide	View C₃₇H₃₄N₂Na₂O₉S₃ Lewis Structure Guide
Dipole Moment (μ)	Not defined — ionic / multi-component substance; polarity is described through ionicity and solvation rather than a molecular dipole
Dielectric Constant (ε_r)	Not quoted — the Debye estimate would inherit a dipole that this method does not deliver reliably for this class of compound
Snyder Polarity Index (P′)	Not conventionally assigned
XlogP3-AA	Not computed (Crippen parameters do not cover every element here) (computed descriptor)

Note: Snyder P′ is a chromatographic solvent scale developed for conventional liquid solvents; the value shown for the dipole is a single-ion-pair calculation about the centre of mass and is origin-dependent for a charged species; XlogP is a calculated partition descriptor, not a direct measure of solvent polarity.

1. Molecular Polarity Analysis of Brilliant Blue FCF: Geometry & Dipole Vector

To determine whether Brilliant Blue FCF (C₃₇H₃₄N₂Na₂O₉S₃) is polar or nonpolar, the decisive question is whether the bond dipoles of the molecule cancel once its three-dimensional shape is taken into account. Brilliant Blue FCF is a sulfonate salt, built from 3 × sulfonate anion (–SO₃⁻). As set out in the C₃₇H₃₄N₂Na₂O₉S₃ Lewis Structure Guide, C₃₇H₃₄N₂Na₂O₉S₃ has 51 heavy atoms, 5 ring systems and 12 rotatable bonds. For FD&C Blue No..

The bond polarities follow from electronegativity. The largest differences in the structure are O–S (ΔEN ≈ 0.86), C–N (ΔEN ≈ 0.49) and C–S (ΔEN ≈ 0.03), so electron density is pulled toward oxygen. In three dimensions, the sulfur centre is tetrahedral with sp3 hybridization with angles close to tetrahedral. Because the substance separates into ions, the molecule is polar but the magnitude of its dipole is not quoted here, because the species is ionic or carries a net charge, so the dipole depends on the choice of origin and is not a molecular constant.

For formulation and process work, the useful consequences are these: the calculated topological polar surface area is 177.8 Å², 0 hydrogen-bond donors and 10 hydrogen-bond acceptors and the Crippen partition coefficient is not quoted, because the parameter set does not cover every element in the molecule. PubChem’s curated experimental record adds: Brilliant Blue FCF is In water, 30 mg/mL (3.0X10+4 mg/L).

Valence-electron check: Counting valence electrons from the formula: carbon contributes 37 × 4 = 148, oxygen contributes 9 × 6 = 54, hydrogen contributes 34 × 1 = 34, sulfur contributes 3 × 6 = 18, nitrogen contributes 2 × 5 = 10 and sodium contributes 2 × 1 = 2, giving 148 + 54 + 34 + 18 + 10 + 2 = 266 valence electrons.

2. Brilliant Blue FCF application: For FD&C Blue No

PubChem’s use and manufacturing record describes Brilliant Blue FCF as follows: For FD&C Blue No. These applications are what make the polarity question practical — solvent choice, extraction recovery, cleaning and formulation all turn on how strongly the molecule interacts with polar phases.

The measured physical behaviour recorded for this substance is consistent with that picture. Solubility: In water, 30 mg/mL (3.0X10+4 mg/L). Physical Description: Other Solid;. Melting Point: 283 °C (decomposes). LogP: log Kow = -4.94 (estimated). These are database values and should be read with the conditions (temperature, purity, pressure) that the source states.

No dilute-gas permittivity is reported here: the Debye estimate would have to inherit a dipole moment that this method does not deliver reliably for this class of compound (the species is ionic or carries a net charge, so the dipole depends on the choice of origin and is not a molecular constant), and for an ionic substance the equation does not apply at all.

Structurally the reactivity sits in 3 × sulfonate anion (–SO₃⁻). That functional inventory, together with the unresolved dipole, is what predicts the solubility and adsorption behaviour: polar groups give the molecule a handle on polar solvents and on polar surfaces, while the hydrocarbon portion resists them.

No GHS hazard statements were retrieved for this substance from the public record used here, so no classification is asserted. The applicable classification must be taken from the supplier’s safety data sheet and from the ECHA or OSHA/NIOSH tables for CAS 3844-45-9.

Industrial Sourcing & Compliance Insight: For Brilliant Blue FCF, the commercially relevant specification is assay, grade, water content and the impurity profile declared on the certificate of analysis, together with the packaging and transport class required for the destination market. With 12 rotatable bonds the conformer population is broad, and the dipole quoted here is for a single low-energy conformer rather than a Boltzmann average. Request the certificate of analysis with the enquiry rather than after it: for a substance handled at industrial scale, the declared impurity profile usually decides whether a lot is usable more often than the nominal purity does.

Recommended Analytical Quality-Control Strategy

Identity confirmation: FTIR or Raman against a reference spectrum, supported by GC–MS or LC–MS where the compound is amenable; this is the fastest way to catch a mis-labelled lot.
Assay / purity: GC-FID or GC-MS for volatile material, HPLC with a validated detector for non-volatile or thermally labile material; state the basis (area %, assay on dried substance, or titrimetric) on the certificate of analysis.
Water content: Karl Fischer titration is the default for a substance whose polarity and hydrogen-bonding capacity make it hygroscopic; moisture is the single most common cause of out-of-specification lots.
Inorganic / ionic content: ion chromatography or ICP-OES for the counter-ion and for trace metals; for salts the counter-ion stoichiometry is part of the assay, not an afterthought.
Physical constants: density, refractive index and boiling or melting range against the published values — cheap, fast and often sufficient to reject a lot before any chromatographic work is done.

In short, specify Brilliant Blue FCF by assay, water content, impurity profile, packaging and transport class, and state the intended application on the enquiry. The polarity analysis above explains behaviour in use; it does not replace a specification.

3. Polarity Comparison: C₃₇H₃₄N₂Na₂O₉S₃ and Related Industrial Fluids

The comparison below places C₃₇H₃₄N₂Na₂O₉S₃ next to structurally related substances from the same catalogue. Dipole moments come from one consistent protocol (GFN2-xTB//MMFF94, gas phase, single conformer) and are quoted only where that protocol has been validated; where it has not, the cell says so instead of giving a number. Permittivities are dilute-gas estimates from the Debye equation, logP values are Crippen calculations, and the solubility column is a qualitative inference from the calculated descriptors rather than a measurement.

Compound	Dipole Moment	Approx. Gas ε_r	log P / XlogP	Water Solubility Behavior	Industrial Sourcing
C₃₇H₃₄N₂Na₂O₉S₃	non-zero, not quoted	—	—	In water, 30 mg/mL (3.0X10+4 mg/L)	See supply listing
C₅₅H₇₂MgN₄O₅	non-zero, not quoted	—	—	Dissolves by dissociation; ionic hydration dominates	See supply listing
C₅₅H₇₀MgN₄O₆	non-zero, not quoted	—	—	Dissolves by dissociation; ionic hydration dominates	See supply listing
C₄₀H₅₆O₂	≈1.02 D (calc.)	≈1.0262	logP ≈ 10.40	Low; hydrophobic (inferred from logP > 4)	See supply listing
C₄₀H₅₆	≈0.18 D (calc.)	≈1.0224	logP ≈ 12.61	Low; hydrophobic (inferred from logP > 4)	See supply listing

The spread across this table is the point: composition alone does not set the polarity verdict. C₃₇H₃₄N₂Na₂O₉S₃ sits where it does because of the balance between its polar functional groups and the asymmetry of its shape, and any of the neighbouring entries can be the better choice once the temperature, the phase and the required polarity window are fixed.

4. Expert R&D Commentary

Expert Chemical Commentary

“C ₃₇H ₃₄N ₂Na ₂O ₉S ₃ is an ionic substance, so the useful question is not "polar or nonpolar" but how the charge is distributed and how strongly the ions are hydrated. No calculated partition coefficient is quoted, because the Crippen parameter set does not cover every element in the molecule. The curated experimental record is consistent: In water, 30 mg/mL (3.0X10+4 mg/L).”

5. Regulatory, Safety & Sustainability Trends

Regulatory status is specific to the substance and to the jurisdiction, and it changes. For CAS 3844-45-9 the authoritative public sources are the ECHA registered-substance database for the EU, and the OSHA and NIOSH tables for occupational exposure in the United States.

No GHS hazard statements for this substance were retrieved from the public database used to build this article, so none are asserted here. Treat the absence of a quoted classification as an instruction to check the supplier’s safety data sheet, not as evidence that the substance is harmless.

No occupational exposure limit for this substance is quoted in this article, because none was present in the database record used here. Publishing a limit that is not on the record would be worse than publishing none: obtain the applicable value from the OSHA Z-table, the NIOSH pocket guide or the equivalent national instrument before designing the ventilation or monitoring programme.

From a compliance and sustainability standpoint, the polarity of C₃₇H₃₄N₂Na₂O₉S₃ is a means rather than an end. It determines which solvent can replace another, how completely the substance can be recovered from a stream, and how much energy the separation will cost — so it belongs in the process justification, while the hazard classification and the exposure limits belong in the safety case.

6. Guidechem's Procurement Tips: What to Specify for Brilliant Blue FCF

A purchase enquiry for Brilliant Blue FCF (CAS 3844-45-9) should state the grade, assay basis, permitted impurity limits, water content, packaging, and the transport and regulatory status required for the destination market. Where the substance is used as a reagent or intermediate, the impurity profile usually matters more than the nominal percentage.

Because polarity governs phase behaviour, it also governs recovery: a polar molecule is easier to strip from a non-polar stream and harder to dry than a non-polar one, and vice versa. Confirm the Guidechem supply listing for current availability and compare lots on the certificate of analysis rather than on the label alone.

Industrial Engineering & Sourcing Specifications

Looking for commercial bulk supplies or technical documentation for Brilliant Blue FCF (CAS 3844-45-9)?

Browse Verified Suppliers & Request Quotes on Guidechem →

Frequently Asked Questions (FAQs)

Is Brilliant Blue FCF polar or nonpolar?

Brilliant Blue FCF is polar. The bond dipoles do not cancel, so the molecule is polar, but no magnitude is quoted because the species is ionic or carries a net charge, so the dipole depends on the choice of origin and is not a molecular constant.

Why is no dipole moment quoted for Brilliant Blue FCF?

The species is ionic or carries a net charge, so the dipole depends on the choice of origin and is not a molecular constant. Rather than publish a number that would be misleading, the article argues the polarity from structure and symmetry; the literature value can be looked up in the NIST or CRC tables if a number is required.

How does the molecular geometry decide the answer?

The sulfur centre is tetrahedral with sp3 hybridization with angles close to tetrahedral. The vector sum of the bond dipoles is what remains once the shape is fixed, so geometry — not the mere presence of polar bonds — is the deciding factor.

What is the dielectric constant of Brilliant Blue FCF?

No permittivity is quoted: the Debye dilute-gas equation does not apply to a charged species.

Does Brilliant Blue FCF have a Snyder polarity index?

Not in routine tabulations. Snyder P′ was developed for conventional liquid chromatographic solvents, and this substance is outside the scope of that scale. Dipole moment, calculated logP and hydrogen-bond counts are the descriptors used here instead.

How does Brilliant Blue FCF behave toward water?

The curated database record states: In water, 30 mg/mL (3.0X10+4 mg/L). No calculated partition coefficient is quoted, because the Crippen parameter set does not cover every element in the molecule.

What should be checked before buying Brilliant Blue FCF?

Grade, assay basis, water content, the declared impurity profile, packaging and the transport classification, plus the regulatory status required for the destination market. Confirm the hazard classification from the supplier’s safety data sheet, since none is asserted here.

References & Academic Databases

PubChem Compound Summary: Brilliant Blue FCF, CAS RN 3844-45-9, CID 19700. National Center for Biotechnology Information. pubchem.ncbi.nlm.nih.gov
ECHA Substance Information: Brilliant Blue FCF, CAS 3844-45-9 — REACH registration status, harmonised classification and regulatory context. European Chemicals Agency.
NIST Chemistry WebBook / CCCBDB: experimental geometry, vibrational data and dipole-moment compilations for Brilliant Blue FCF. National Institute of Standards and Technology.
CRC Handbook of Chemistry and Physics, 92nd ed. (Haynes, W. M., ed.), CRC Press, 2011 — electronegativity, dielectric constant and dipole-moment tables.
Nelson, R. D.; Lide, D. R.; Maryott, A. A.: Selected Values of Electric Dipole Moments for Molecules in the Gas Phase, NSRDS-NBS 10, National Bureau of Standards, 1967.
Snyder, L. R.: solvent-polarity classification and the P′ scale for liquid chromatographic solvents. The P′ scale is defined only for conventional liquid solvents and is not assigned to substances outside that scope.
Bannwarth, C.; Ehlert, S.; Grimme, S.: GFN2-xTB — an accurate and broadly parametrised self-consistent tight-binding quantum chemical method with multipole electrostatics and density-dependent dispersion contributions. J. Chem. Theory Comput. 2019, 15 (3), 1652–1671.
RDKit / Halgren, T. A.: MMFF94 force field for geometry generation (J. Comput. Chem. 1996, 17, 490–519) and the RDKit cheminformatics toolkit used for the Crippen logP, TPSA and hydrogen-bond descriptors quoted here.

Technical note: Dipole moment, relative permittivity, Snyder P′ and calculated logP are not interchangeable descriptors. For C ₃₇H ₃₄N ₂Na ₂O ₉S ₃ no dipole magnitude is reported: the species is ionic or carries a net charge, so the dipole depends on the choice of origin and is not a molecular constant. The polarity argument therefore rests on symmetry and structure alone; where a number is needed, take it from the NIST Computational Chemistry Comparison and Benchmark Database or the CRC Handbook rather than from a calculation that this benchmark does not support. This molecule contains a hypervalent or heavier main-group centre for which the tight-binding parametrisation is less reliable, hence the "indicative" label. For this charged species the dipole was computed about the centre of mass; for a net-charged system that quantity depends on the choice of origin and is reported only as a reference number. With 12 rotatable bonds the quoted dipole belongs to one low-energy conformer, not to a conformational ensemble. Procurement and process decisions should rest on application-specific specifications — grade, assay, water content and impurity profile — supported by measured property data, rather than on a single polarity number.

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Brilliant Blue FCF Polarity