  Fe-gluconate, Fe(C_6H_11O_7_2xH_2O is a well-known material widely used for
iron supplementation. On the other hand, it is used in food industry as a
coloring agent, in cosmetic industry for skin and nail conditioning and
metallurgy. Despite of wide range of applications its physical properties were
not studied extensively. In this study, Fe-gluconate with three different
amount of water viz. x=2 (fully hydrated, 0 < x < 2 (intermediate) and x=0
(dry) was investigated by means of X-ray diffraction (XRD) and M\"ossbauer
spectroscopic (MS) methods. The former in the temperature range of 20-300 K,
and the latter at 295 K. Based on the XRD measurements crystallographic
structures were determined: monoclinic (space group I2) for the hydrated sample
and triclinic (space group P1) for the dry sample. The partially hydrated
sample was two-phased. Unit cells parameters for both structures show strong,
very complex and non-monotonic temperature dependences. M\"ossbauer
spectroscopic measurements gave evidence that iron in all samples exist in form
of Fe(II) and Fe(III) ions. The amount of the latter equals to ca.30% in the
hydrated sample and to ca.20% in the dry one.
