It is commonly encountered as the green hexahydrate, Fe(NO3)2·6H2O, which is a metal aquo complex, however it is not commercially available unlike iron(III) nitrate due to its instability to air.

The salt is soluble in water and serves as a ready source of ferrous ions.

Nonetheless, the nature of the aquo complex [Fe(H2O)6]2+ is well known and relatively insensitive to the anion.

[5] Both [Fe(H2O)6]n+ complexes are high spin, which results in pale colors, paramagnetism, and weak Fe-O bonds.

Iron(II) nitrate can be produced in multiple ways, such as the reaction of iron metal with cold dilute nitric acid: If this reaction is conducted below -10 °C, nonahydrate is produced.