Sodium Phosphate Dibasic: Properties, Benefits, Grades & Applications

What is Sodium Phosphate Dibasic used for? Sodium Phosphate Dibasic (disodium hydrogen phosphate) is an inorganic phosphate compound widely used in laboratory research, pharmaceutical formulations, food processing, chemical manufacturing, water treatment, and various industrial applications requiring controlled pH and phosphate availability. Allan Chemical lists Sodium Phosphate Dibasic Anhydrous (CAS 7758-79-4) in ACS and FCC grades, and Sodium Phosphate Dibasic 7H₂O (CAS 7782-85-6) in ACS and USP grades — see the full Sodium Phosphate Dibasic listing.

What Is Sodium Phosphate Dibasic?

Sodium Phosphate Dibasic, also known as disodium hydrogen phosphate, is a sodium salt of phosphoric acid (see the PubChem compound record for detailed chemical identity data). It is commonly available in anhydrous and hydrated forms, including dihydrate and heptahydrate forms.

The chemical is valued for its ability to act as a buffering agent and phosphate source. It can help maintain a controlled pH in aqueous formulations and is often combined with other phosphate salts, such as sodium phosphate monobasic, to prepare buffer systems.

Allan Chemical Corporation lists Sodium Phosphate Dibasic Anhydrous under CAS Number 7758-79-4, with ACS and FCC grades. AllanChem also lists Sodium Phosphate Dibasic 7H₂O under CAS Number 7782-85-6, with ACS and USP grades.

Physical & Chemical Properties

Hydrated forms contain water of crystallization and therefore have different molecular weights and physical characteristics. The exact assay, moisture content, pH, and impurity specifications should be confirmed using the current product specification and lot-specific Certificate of Analysis.

Sodium Phosphate Dibasic Grades and Quality Considerations

The correct grade should be selected based on the final application.

Grade Overview

AllanChem lists Sodium Phosphate Dibasic Anhydrous in ACS and FCC grades, while its Sodium Phosphate Dibasic 7H₂O listing includes ACS and USP grades. Grade selection is important because different applications may have specific requirements for assay, elemental impurities, microbiological quality, moisture, and other parameters.

Why Manufacturers Choose Sodium Phosphate Dibasic

• Effective buffering capability
• Provides a controlled source of phosphate
• Good water solubility
• Useful for maintaining desired pH ranges
• Available in anhydrous and hydrated forms
• Suitable for laboratory buffer preparation
• Used in pharmaceutical formulations
• Applicable to food-processing applications
• Useful in chemical and industrial processes
• Available in multiple quality grades

Its versatility allows manufacturers and laboratories to select a form and grade appropriate for their specific requirements. Buyers sourcing multiple specialty inorganics may also review Allan Chemical’s Calcium Chloride Anhydrous and Boric Acid listings for related laboratory and industrial-grade materials.

Applications Across Industries

Pharmaceutical and Healthcare Applications

Pharmaceutical applications are an important area for sodium phosphate compounds. Sodium Phosphate Dibasic can be used as a buffering agent, pH-control ingredient, and formulation component. It can be incorporated into formulations where maintaining a stable pH is important for product performance and stability. Phosphate buffer systems are also widely used in pharmaceutical research, formulation development, and laboratory testing.

• Pharmaceutical formulations
• Buffer solutions
• Laboratory preparation of pharmaceutical samples
• Research and development
• pH adjustment
• Formulation stabilization

For pharmaceutical applications, manufacturers should select an appropriate compendial grade and verify that the product meets the relevant specification.

Food and Beverage Applications

Food-grade phosphate salts are used in a range of food-processing applications. Sodium Phosphate Dibasic can function as a buffering agent, stabilizer, emulsifying aid, and formulation ingredient, depending on the specific food system. It can help control acidity and maintain desired formulation characteristics. The U.S. Food and Drug Administration (FDA) maintains current guidance on permitted food-additive uses for phosphate salts.

• Processed food formulations
• Dairy-related applications
• Beverage formulations
• Food processing
• pH control
• Stabilization systems

For food applications, an appropriate FCC or applicable food-grade specification should be selected.

Laboratory and Research Applications

ACS-grade Sodium Phosphate Dibasic is widely useful in laboratory and research environments. One of its best-known functions is as a component of phosphate buffer systems. When combined with sodium phosphate monobasic, it can help prepare solutions with controlled pH.

• Buffer preparation
• Analytical chemistry
• Biological research
• Biochemical experiments
• Sample preparation
• Chemical synthesis
• Research and development
• pH-control studies

Purity and consistency are particularly important when the chemical is used in analytical procedures because impurities can interfere with experimental results.

Chemical Manufacturing and Industrial Applications

Sodium Phosphate Dibasic can also be used as a phosphate source in chemical processing. Its buffering and formulation properties make it useful in selected industrial processes where pH control or phosphate functionality is required. It can also serve as an intermediate or formulation component in products containing phosphate salts.

• Chemical processing
• Formulation manufacturing
• Specialty chemical production
• Detergent-related formulations
• Surface treatment processes
• Laboratory chemical manufacturing

The appropriate grade should be selected based on the technical specifications required by the process.

Water Treatment and Other Applications

Phosphate compounds are used in various water-treatment and water-conditioning processes because phosphate chemistry can help control mineral interactions and water chemistry. Sodium Phosphate Dibasic may be used in selected water-treatment formulations and research involving aqueous systems.

• Buffer solutions
• Water-conditioning formulations
• Research into phosphate chemistry
• Cleaning and processing formulations
• Specialty industrial formulations

Actual suitability depends on the treatment process, water chemistry, regulatory requirements, and required purity.

Advantages at a Glance

• Effective phosphate buffering capability
• Water-soluble inorganic salt
• Available in anhydrous and hydrated forms
• ACS grade for laboratory applications
• FCC grade availability for applicable food uses
• USP grade available for selected hydrated material
• Useful in pharmaceutical formulations
• Suitable for laboratory and research applications
• Applicable to chemical and industrial processes
• Useful for controlled pH systems

Regulatory & Safety Considerations

Sodium Phosphate Dibasic should be handled according to its current Safety Data Sheet (SDS) and the requirements applicable to its intended use. Consult CDC/NIOSH guidance for general workplace exposure and handling recommendations.

• Avoid unnecessary inhalation of dust.
• Avoid direct contact with eyes.
• Use appropriate protective gloves and eye protection.
• Maintain suitable ventilation when handling powders.
• Keep containers properly labeled.
• Avoid contamination of food or other materials.
• Follow applicable workplace handling procedures.

Different grades and hydration states may have different specifications and handling requirements. Always refer to the SDS for the specific product being used. The European Chemicals Agency (ECHA) maintains substance information relevant to markets outside the U.S.

Storage & Handling Best Practices

Proper storage helps preserve product quality and prevent contamination.

• Keep containers tightly closed.
• Store in a cool, dry environment.
• Protect from excessive moisture.
• Keep away from incompatible materials.
• Use clean, dry handling equipment.
• Maintain original labeling.
• Follow supplier-specific storage instructions.

For hydrated grades, moisture conditions should be controlled because changes in environmental conditions can affect the physical characteristics and water content of the material.

What to Verify Before Sourcing It

• Hydration state: Confirm whether you need anhydrous or 7H₂O (heptahydrate) — these are not interchangeable on a mass-for-mass basis.
• Grade: ACS for laboratory work, FCC for food applications, or USP for pharmaceutical use.
• CAS Number: Confirm chemical identity against 7758-79-4 (anhydrous) or 7782-85-6 (7H₂O).
• Certificate of Analysis (COA): Request lot-specific quality information.
• Safety Data Sheet (SDS): Review for safe handling and regulatory compliance.
• Regulatory fit: For food or pharmaceutical applications, verify the applicable compendial or food regulations before use.

Frequently Asked Questions

What is Sodium Phosphate Dibasic?

Sodium Phosphate Dibasic, or disodium hydrogen phosphate, is an inorganic sodium phosphate salt used primarily as a buffering agent and phosphate source.

What is the CAS number of Sodium Phosphate Dibasic Anhydrous?

The CAS number is 7758-79-4.

What grades of Sodium Phosphate Dibasic are available from AllanChem?

AllanChem lists ACS and FCC grades for Sodium Phosphate Dibasic Anhydrous. It also lists Sodium Phosphate Dibasic 7H₂O in ACS and USP grades.

What is Sodium Phosphate Dibasic used for?

It is used in laboratory buffers, pharmaceutical formulations, food processing, chemical manufacturing, water-treatment formulations, and other applications requiring phosphate functionality or pH control.

What is the difference between anhydrous and hydrated Sodium Phosphate Dibasic?

Anhydrous Sodium Phosphate Dibasic contains no water of crystallization, while hydrated forms contain a defined amount of water within their crystal structure. They have different molecular weights and should be selected according to the formulation or process requirements.

Is Sodium Phosphate Dibasic soluble in water?

Yes. Sodium Phosphate Dibasic is water-soluble and is commonly used in aqueous buffer systems.

Is Sodium Phosphate Dibasic used in laboratory buffers?

Yes. It is commonly combined with sodium phosphate monobasic to prepare phosphate buffer systems with controlled pH.

Can Sodium Phosphate Dibasic be used in food applications?

Appropriately specified food-grade material can be used in food-related applications. The applicable food regulations and grade requirements should always be verified for the intended use.

What documentation should be requested when purchasing Sodium Phosphate Dibasic?

Buyers may request a Certificate of Analysis (COA), Safety Data Sheet (SDS), product specification, lot information, and applicable grade or compendial documentation.

How should Sodium Phosphate Dibasic be stored?

It should generally be stored in a tightly closed container in a cool, dry environment and protected from excessive moisture and contamination.

References

Internal resources:

1. Allan Chemical Corporation — Sodium Phosphate Dibasic
2. Allan Chemical — Laboratory Reagents, Biochemicals, Catalysts & R&D
3. Allan Chemical — Food & Beverage Chemicals
4. Allan Chemical — Calcium Chloride Anhydrous
5. Allan Chemical — Boric Acid

External resources:

1. PubChem — Disodium Phosphate Compound Summary (National Library of Medicine)
2. CDC/NIOSH — Workplace Safety & Health Topics
3. U.S. Food and Drug Administration (FDA)
4. European Chemicals Agency (ECHA) — Substance Information

This article is for general information and sourcing guidance. Always consult the current official product specification, SDS, applicable regulations, and qualified professionals for your specific application.