dietary iron iron(2+) iron(2+) Fe CAS:15438-31-0 CHEBI:49599 Fe(II) FE (II) ION iron(2+) ion Fe2+ Fe(2+) PDBeChem:FE2 55.93384 InChI=1S/Fe/q+2 55.84500 iron(II) cation [Fe++] CHEBI:29033 Gmelin:6845 CHEBI:13319 +2 iron ion(2+) CHEBI:34754 Iron(2+) KEGG:C14818 CHEBI:24876 chebi_ontology CWYNVVGOOAEACU-UHFFFAOYSA-N CHEBI:21129 Ferrous ion iron(2+) CHEBI:13321