In the presence of Cs+–K 2.2.2 and NCA [18F]fluoride ion In glass vials, a reaction of no-carrier-added (NCA) [18F]fluoride ion with a low amount of xenon difluoride (11 mmol) in the presence of Cs+–K 2.2.2 in dichloromethane (300 mL) for 90 min produced no [18F]XeF2 but an increase in amount of xenon difluoride to 27 mmol increased RCY to 26% over 90 min.