Sulfur hexafluoride sf6 Specialty gases Cas no.: 2551-62-4 Einecs no.: 219-854-2 Un no.: un1080 Purity: 99.995%-99.999% Dot class: 2.2 Appearance: colorless Grade standard: electronic grade, industrial grade Dielectric medium: Sf6 is used in the electrical industry as a gaseous dielectric medium for high-voltage circuit breakers, switchgear, and other electrical equipment, often replacing oil filled circuit breakers (ocbs) that can contain harmful pcbs. Medical use: Sf6 is used to provide a tamponade or plug of a retinal hole in retinal detachment repair operations in the form of a gas bubble. Tracer compound. As an etchant, as inert gas to fill casting forms, as a filler gas in tennis balls and so on.