Procedure for the Synthesis of SF5Cl Trichloroisocyanuric acid (9.60 g, 4.5 equiv.) was added to a flame-dried 100 mL pressure flask equipped with a stir bar under Ar. Then, spray-dried potassium fluoride (4.84 g, 9.0 equiv.) was added, followed by sulfur (297 mg, 1.0 equiv.). MeCN (46 mL) was added via syringe and the reaction vessel was tightly capped, wrapped in aluminum foil, and transported to the fume hood where it was allowed to stir behind a blast shield at room temperature for 48 h. After completion, the reaction vessel was submerged in a -78 °C dry ice acetone bath. When the solution reached -78 °C, anhydrous hexanes (or n-pentane, 29 mL) was added quickly via syringe, while avoiding outgassing. The reaction vessel was then tightly sealed and allowed to warm to room temperature while stirring. Once the mixture reached room temperature, the solution was transferred to an ovendried separatory funnel. The MeCN layer was discarded and the hexanes (or n-pentane) solution containing SF5Cl was stored in a Schlenk flask under Argon and wrapped in aluminum foil.