FE (II) ION non-polymer HETAI Fe 2 1999-07-08 2011-06-04 N REL 55.845 FE2 N N RCSB FE FE 2 0 N N N 0.000 0.000 0.000 0.000 0.000 0.000 FE FE2 1 [Fe+2] [Fe++] [Fe++] [Fe+2] [Fe+2] InChI=1S/Fe/q+2 CWYNVVGOOAEACU-UHFFFAOYSA-N iron(2+) iron(+2) cation RCSB RCSB