Crystalline phases of solid oxygen

X-ray studies of solid oxygen began in the 1920s, and at present six distinct crystallographic forms have been unequivocally identified. The a, p, and y phases exist at ambient pressure and low temperature. At T = 295 K, oxygen solidifies to form the ft phase at 5.4 GPa, which transforms into the orange 5 

Molecular packing in the crystal structure of e-oxygen the solid and open lines indicate covalent and weak bonds, respectively, (a) C-centered layer of (02)4 clusters viewed along the c axis (b) the same layer viewed along the b axis. Symmetry codes Ax, y, z B x, y, z Cx, y, z. 

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