Hydrogen Peroxide Vapour
Hydrogen peroxide has the formula H2O2. In its pure form, it is a colourless liquid. The boiling point of 'pure' H2O2 has been extrapolated as being 150.2 °C. This is around 50 °C higher than water. But, in practice, 'pure' hydrogen peroxide will undergo potentially explosive thermal decomposition if raised to this temperature.
In aqueous solutions, hydrogen peroxide behaves differently from the pure material. This is due to the effects of hydrogen bonding between water and hydrogen peroxide molecules. Hydrogen peroxide and water form a eutectic mixture, exhibiting a depressed 'boiling point' in relation to the mean of both boiling points (125.1 °C). This boiling point occurs at 114 °C i.e. it is 14 °C greater than that of pure water and 36.2 °C less than that of pure hydrogen peroxide.
When heated sufficiently, aqueous hydrogen peroxide will become a vapour. This vapour will then behave like a 'lazy' gas in may respects, with the ability to permeate through an enclosed space until all exposed surfaces have contact with the vapour. At this interface, the vapour can begin to 'condense' onto the the surface, depending on temperatures and relative humidity.