Phosphoric acid, monosodium salt (CAS 7558-80-7) — Citrus Non-odorous Note Fragrance Ingredient

ByThe Good Scents
Citrus · Floral

Phosphoric acid, monosodium salt

CAS 7558-80-7

Origin
synthetic
Note
Non-odorous
IFRA
Generally safe
Data as of: Apr 2026

What Is Phosphoric acid, monosodium salt?

Monosodium phosphate is a synthetic compound primarily used as a pH adjuster and buffering agent in cosmetics and personal care products. It helps stabilize formulations and maintain product consistency. While not a fragrance ingredient itself, it plays a supporting role in many scented products by ensuring the fragrance components remain stable and effective over time.

Safety Profile

GENERALLY SAFE
Generally safeUse with awarenessProfessional use
✓ Approved for use in cosmetics
✓ No known fragrance-related hazards
CAS
7558-80-7
Formula
Mixture
MW
Variable
Odor Family
Citrus · Floral
Layer 1 · Enthusiast

What Does Phosphoric acid, monosodium salt Smell Like?

Monosodium phosphate is odorless and does not contribute directly to fragrance profiles. As a pH regulator, it works behind the scenes to maintain the stability and performance of aromatic compounds in formulations. Its presence helps prevent degradation of delicate top notes and extends the shelf life of fragrance compositions without imparting any detectable scent of its own.

Layer 2

2D Molecular Structure

Monosodium phosphate

SMILES: [Na+].OP(O)([O-])=O

Chemistry, Properties & Perfumer Guide

The Chemistry

Monosodium phosphate is an inorganic salt formed by the partial neutralization of phosphoric acid with sodium hydroxide. It exists as a white, crystalline powder that is highly soluble in water. The compound dissociates in solution to provide buffering capacity, helping maintain stable pH levels in cosmetic and personal care formulations. While not a fragrance material itself, its chemical properties make it valuable for stabilizing volatile aromatic compounds.

Physical & Chemical Properties

AppearanceWhite crystalline powder
SolubilityHighly water soluble

Perfumer Guide

Note Position
Non-odorous
Volatility
N/A
Blending
N/A
ApplicationTypical %RangeNotes
Cosmetic Formulations0.1-1%Up to 3%pH adjustment and buffering
Personal Care Products0.5-2%Up to 5%Stabilizer in fragranced products

Classic Accords

Tip: Use as needed to maintain optimal pH for fragrance stability without exceeding recommended concentrations.

Alternatives & Comparisons

1
Disodium phosphate CAS 7558-79-4

Provides stronger buffering capacity at higher pH ranges when more alkaline conditions are required in formulations.

2
Citric acid CAS 77-92-9

Organic acid alternative for pH adjustment in natural or milder formulations where inorganic phosphates are undesirable.

Layer 3

Safety, Regulatory & Sustainability

⚠ Regulatory Disclaimer

General reference only. Consult current IFRA Standards Library before formulating.

IFRA Status

Not restricted by IFRA as it is not a fragrance material.

RIFM Assessment

Not evaluated by RIFM as it is not a fragrance ingredient.

Sustainability

Monosodium phosphate is synthetically produced from abundant mineral sources. While not renewable, its production is energy-efficient and generates minimal waste. As a non-volatile, non-bioaccumulative compound, it poses low environmental risk when properly disposed. Formulators should consider the total phosphate load in products to minimize potential aquatic ecosystem impacts.

Explore Phosphoric acid, monosodium salt

Browse essential oils and aroma compounds.

Browse on iHerb →

Affiliate disclosure: we may earn a small commission at no extra cost to you.

References

    Data: PubChem (NIH), PubMed, RIFM, IFRA. Last reviewed: Apr 2026.

    Report a data error

    Layer 3 · Practical

    • Molecular Weight: 119.98 g/mol

    Ingredient Data Sheet

    CAS 7558-80-7

    Physical Properties

    Molecular Weight119.977 g/mol🔬 PubChem
    SMILESOP(=O)(O)[O-].[Na+]🔬 PubChem
    Data Sources & Attribution
    Physical data: PubChem (NIH/NLM), U.S. EPA CompTox Dashboard, EPA OPERA models, RDKit. Odor & flavor: Arctander (Perfume & Flavor Chemicals), Fenaroli's Handbook of Flavor Ingredients, Leffingwell. Thresholds: van Gemert (Compilations of Odour Threshold Values). Regulatory: IFRA Standards 51st, FEMA GRAS. Trade names: Surburg (Common Fragrance & Flavor Materials). All data compiled and cross-referenced for perfumertools.com.

    Physicochemical Properties

    DTXSID: DTXSID7035222

    Physical Properties

    Molecular Weight 119.976 g/mol🔬 EPA CompTox
    Density 2.359 g/cm^3🔬 EPA CTX

    Partition & Solubility

    LogP (Octanol-Water) -4.557 dimensionless💻 Computed
    Water Solubility 7.085 mol/L🔬 EPA CTX

    Molecular Descriptors

    Topological Polar Surface Area 80.59 Ų💻 Computed
    H-Bond Donors 2 count💻 Computed
    H-Bond Acceptors 2 count💻 Computed
    Rotatable Bonds 0 count💻 Computed
    Aromatic Rings 0 count💻 Computed
    Molar Refractivity 12.04 cm^3/mol💻 Computed

    Data Sources:

    🔬 EPA Experimental data from U.S. EPA CompTox Chemicals Dashboard & CTX APIs. 📊 OPERA Predicted using EPA's OPERA QSAR models. 💻 Computed Calculated from SMILES using RDKit.

    Similar Posts