text: In 1970-75, Giguère et al. observed infrared and Raman spectra of dilute aqueous solutions of trioxidane. In 2005, trioxidane was observed experimentally by microwave spectroscopy in a supersonic jet. The molecule exists in a skewed structure, with an oxygen–oxygen–oxygen–hydrogen dihedral angle of 81.8°. The oxygen–oxygen bond lengths of 142.8 picometer are slightly shorter than the 146.4 pm oxygen–oxygen bonds in hydrogen peroxide. Various dimeric and trimeric forms also seem to exist.
  There is a trend of increasing gas-phase acidity and corresponding pK as the number of oxygen atoms in the chain increases in HOH structures (n=1,2,3).