Iron(II) nitrate is the nitrate salt of iron(II). 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.

Structure

No structure of any salt Fe(NO3)2·xH2O has been determined by X-ray crystallography. Nonetheless, the nature of the aquo complex [Fe(H2O)6]2+ is well known and relatively insensitive to the anion. The Fe-O distances are longer for [Fe(H2O)6]2+ (2.13 Å) than for the ferric analogue [Fe(H2O)6]3+ (1.99 Å).[5] Both [Fe(H2O)6]n+ complexes are high spin, which results in pale colors, paramagnetism, and weak Fe-O bonds.

The solubility graph of iron(II) nitrate

Production

Iron(II) nitrate can be produced in multiple ways, such as the reaction of iron metal with cold dilute nitric acid:

source: https://en.wikipedia.org/wiki/Iron(II)_nitrate