methylphosphonyl difluoride methylphosphonyl difluoride methylphosphonyl difluoride (df), also known as ea-1251 or difluoro, is a chemical weapon precursor. its chemical formula is ch3pof2. it is a schedule 1 substance under the chemical weapons convention. it is used for production of sarin and soman as a component of binary chemical weapons; an example is the m687 artillery shell, where it is used together with a mixture of isopropyl alcohol and isopropyl amine, producing sarin. methylphosphonyl difluoride names preferred iupac name methylphosphonic difluoride other names methylphosphonyl difluoridemethylphosphonoyl difluoride, ea-1251 identifiers cas number 676-99-3 y 3d model (jsmol) interactive image beilstein reference 4-04-00-03508 chemspider 62813 mesh difluoride methylphosphonic difluoride pubchem cid 69610 unii z7v517240k y comptox dashboard (epa) dtxsid5060980 inchi inchi=1s/ch3f2op/c1-5(2,3)4/h1h3key: pqiosykvbbwrri-uhfffaoysa-n smiles cp(f)(f)=o properties chemical formula ch3pof2 molar mass 100.00 appearance colorless liquid odor pungent, acid-like density 1.359 g/ml (77°f) melting point −37 °c; −35 °f; 236 k boiling point 100 °c; 212 °f; 373 k solubility in water decomposes vapor pressure 36 mmhg (77°f) hazards occupational safety and health (ohs/osh): main hazards corrosive, toxic except where otherwise noted, data are given for materials in their standard state (at 25 °c , 100 kpa). infobox references preparation methylphosphonyl difluoride can be prepared by reacting methylphosphonyl dichloride with hydrogen fluoride (hf) or sodium fluoride (naf). safety methylphosphonyl difluoride is both reactive and corrosive. it is absorbed through skin and causes burns and mild nerve agent symptoms. it reacts with water, producing hf fumes and methylphosphonic acid as a result. it is also capable of corroding glass. significance in international relations in 2013–2014, the stockpile of chemicals covered by the cwc was removed from syria and destroyed. of the stockpile, 581 tons (over 96%) of the stockpile was df. it was destroyed by the u.s. army on the mv cape ray by hydrolysis.