metal_sdf/NA_ideal.sdf

NA
  -OEChem-03222417103D

  1  0  0     0  0  0  0  0  0999 V2000
    0.0000    0.0000    0.0000 Na  0  3  0  0  0  0  0  0  0  0  0  0
M  CHG  1   1   1
M  END
> <OPENEYE_ISO_SMILES>
[Na+]

> <OPENEYE_INCHI>
InChI=1S/Na/q+1

> <OPENEYE_INCHIKEY>
FKNQFGJONOIPTF-UHFFFAOYSA-N

> <FORMULA>
Na+

$$$$