Sodium trifluoromethanesulfinate is an organosulfur compound with the formula CF₃SO₂Na. It is a white to off-white crystalline powder that is hygroscopic and soluble in water and polar organic solvents. This compound serves as a versatile and stable source of the trifluoromethyl radical (•CF₃) and the trifluoromethanesulfinyl (CF₃SO•) radical under various reaction conditions. Its primary application is as a key reagent in organic synthesis for the trifluoromethylation and trifluoromethylsulfinylation of a wide range of substrates, including arenes, heteroarenes, alkenes, and carbonyl compounds. These reactions are crucial for introducing the trifluoromethyl group, which is a privileged motif in medicinal chemistry, agrochemicals, and materials science due to its ability to enhance metabolic stability, lipophilicity, and binding affinity. The reagent is particularly valued for its operational simplicity, commercial availability, and compatibility with transition-metal catalysis, photoredox catalysis, and electrochemical methods. Beyond radical chemistry, it is also used as a precursor for other trifluoromethyl-containing reagents and as a building block in the synthesis of more complex molecules. Handling requires standard precautions for laboratory chemicals, avoiding inhalation and contact with skin.