2FK
  -OEChem-11082419093D

  2  1  0     0  0  0  0  0  0999 V2000
    0.0000    0.0000   -0.5010 O   0  5  0  0  0  0  0  0  0  0  0  0
    0.0000    0.0000    0.5010 O   0  0  0  0  0  0  0  0  0  0  0  0
  1  2  2  0  0  0  0
M  CHG  1   1  -1
M  END
> <OPENEYE_ISO_SMILES>
[O-]=O

> <OPENEYE_INCHI>
InChI=1S/O2/c1-2/q-1

> <OPENEYE_INCHIKEY>
MXDZWXWHPVATGF-UHFFFAOYSA-N

> <FORMULA>
O2-

$$$$