THE OXYGEN RED PHASE gets its name from the fact that this form of solid oxygen comprised of oxygen-4 molecules is deeply red in color, and gets more red at higher pressures. The red phase has now been studied in detail by physicists in Italy and their results suggest that at pressures above 10 GPa two O₂ molecules combine into an O₄ molecule. The pressure is necessary for altering (by brute force) the chemical bonds at work inside this molecular solid. By recording the vibrational properties of oxygen solids at pressures up to 63 GPa, Roberto Bini (bini@chim.unifi.it, 011-39-055-230-7864) and his colleagues at the European Laboratory for Nonlinear Spectroscopy in Florence have concluded that the process whereby O2 molecules form into O4 units could be a kind of prelude to oxygen's transformation into longer chains (polymers) and then into a metal (superconducting oxygen was reported by Shimizu et al., in Nature, 25 June 1998), (Gorelli et al., Physical Review Letters, 15 November. Journalists can obtain the article at the Physics News Select Articles website)