The propionate (IUPAC name propanoate) ion's C2H5COO− (propionic acid minus one hydrogen ion). A propionate or propanoate compound's a salt or ester of propionic acid. Propionates/propanoates shouldn't be confused with propenoates, the ions/salts/esters of propenoic acid (also known as 2-propenoic acid or acrylic acid). Examples Sodium propionate, Na(C2H5CO2) Methyl propionate, (C2H5(CO)OCH3) Calcium propionate, Ca(C2H5CO2)2 Potassium propionate, K(C2H5CO2) Testosterone propionate Fl… (More on Propionate)