Solid Oxygen

By rapid evaporation and consequent cooling, or by cooling in liquid hydrogen, liquid oxygen can be converted into a bluish-white solid oxygen of density 1.4256 at -252.5° C. and melting at -219° C. under a vapour pressure of 0.9 mm. The solid exhibits allotropy, α, β, and γ forms being recognised. The transition between the α and β forms occurs at -249.5° C. and between the and y forms at -230.5° C.