# Are there any other (meta)stable oxygen molecules beyond O3?

Apart from Ozone, are there any longer oxygen molecules that are at least stable for short amounts of time? What configurations would that be?

Wiberg describes it's synthesis from dioxygen in a mass-spectrometer employing the "neutralisation-reionisation-technique" (I am translating and paraphrasing at the same time, there might be something lost in translation.) It's stable time frame is in the micro second area. The decomposition barrier of $\ce{O4}$ is about 25 kJ/mol. The structure is not known, but most likely an aggregate of two oxygen molecules, i.e. $\ce{(O2)2}$. In lower concentrations $\ce{O4}$ might be found in liquid oxygen and they may be a template for the ε-high pressure modification of solid oxygen forming at 0.6 Mbar.