Ethylphosphonic acid
Ethylphosphonic acid (CAS 6779-09-5), with the chemical formula C2H5P(O)(OH)2 and a molecular weight of 110.05 g/mol, is an organophosphorus compound. It is primarily utilised as a building block in chemical synthesis and as a phosphonic acid derivative. This compound serves as a valuable reagent in organic chemistry research and development, contributing to the creation of more complex molecules.

Internal Standard in Analytical Chemistry
Ethylphosphonic acid has been employed as an internal standard for the quantitative determination of fosfomycin in biological samples, such as human plasma. This application highlights its utility in analytical method development and validation.
Organic Synthesis Intermediate
As an organic building block, ethylphosphonic acid can be incorporated into synthetic pathways for the development of novel organophosphorus compounds. Its reactive phosphonic acid moiety allows for various chemical transformations.
Phosphorus Compound Research
This compound belongs to the class of phosphonic and phosphinic acids, making it relevant for research into phosphorus chemistry. It can be used to study reaction mechanisms or develop new phosphorus-containing materials.
| Molecular weight | 110.05 |
|---|---|
| Linear formula | C2H5P(O)(OH)2 |
| Assay | 98% |
| Application | Ethylphosphonic acid was used as an internal standard in the determination of fosfomycin in human plasma1. |
| Melting point | 61-63 °C(lit.) |

Hazard statements
- H314Causes severe skin burns and eye damage
Precautionary statements
- P280Wear protective gloves, clothing and eye/face protection
- P305IF IN EYES
- P310Immediately call a POISON CENTER or doctor
| Protective equipment | Eyeshields, Faceshields, full-face particle respirator type N100 (US), Gloves, respirator cartridge type N100 (US), type P1 (EN143) respirator filter, type P3 (EN 143) respirator cartridges |
|---|---|
| Transport (UN / ADR) | UN 3261 8 / PGII |
| Water hazard class (WGK, DE) | 3 |
| Hazard codes (EU) | C |
| Risk statements (R) | 34 |
| Safety statements (S) | 26-27-28-36/37/39-45 |
Hazard information is provided for guidance. Always consult the product Safety Data Sheet (SDS), available on request, before handling.
Documentation
Every batch ships with a Certificate of Analysis covering assay, identity and purity; the grade is confirmed against your enquiry. Safety Data Sheets and technical data sheets are available on request.
Supply & logistics
Samples for technical evaluation; bulk MOQ by grade and packaging. In-stock material ships in 7–10 working days, worldwide, with full export documentation.
What is Ethylphosphonic acid used for?
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Ethylphosphonic acid is used as an internal standard in analytical chemistry, for example, in the determination of fosfomycin, and as a building block in organic synthesis and phosphorus compound research.
What is the CAS number and formula for Ethylphosphonic acid?
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The CAS number for Ethylphosphonic acid is 6779-09-5, and its chemical formula is C2H5P(O)(OH)2.
What grade and purity does Tech Serve Solutions supply?
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Tech Serve Solutions supplies Ethylphosphonic acid with an assay of 98%. We do not represent this product as USP, BP, EP, or any other pharmacopoeia grade unless explicitly stated in the product specifications.
How should Ethylphosphonic acid be handled safely?
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Ethylphosphonic acid causes severe skin burns and eye damage (H314). Appropriate personal protective equipment, including eyeshields, face shields, gloves, and respiratory protection (e.g., N100 respirator), must be used. Handle in a well-ventilated area and seek immediate medical attention in case of contact.
Is Ethylphosphonic acid a controlled substance?
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Based on the provided data, Ethylphosphonic acid (CAS 6779-09-5) is not listed as a controlled substance. For specific regulatory information in your jurisdiction, please consult relevant authorities.
How can I request a sample or quote for Ethylphosphonic acid?
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To request a sample or obtain a quote for Ethylphosphonic acid, please contact the TSS sales department through our website or by phone, providing the product name and CAS number.
How is Ethylphosphonic acid shipped?
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Ethylphosphonic acid is classified under UN 3261, Hazard Class 8, Packing Group II. Shipments are handled in accordance with regulations for corrosive solids, acidic, organic, n.o.s.
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