Nitrous oxide n2o Medical gases Cas no.: 10024-97-2 Einecs no.: 233-032-0 Un no.: un1070 Purity: 99.9%, 99.999% Dot class: 2.2 Appearance: colorless Grade standard: electronic grade, industrial grade, medical grade Medical: It is used as a carrier gas in a 2:1 ratio with oxygen for more powerful general anaesthetic drugs such as sevoflurane or desflurane. Electronic: It is used in combination with silane for chemical vapor deposition of silicon nitride layers; it is also used in rapid thermal processing to grow high quality gate oxides.