  Low temperature M\"ossbauer spectroscopic and magnetization measurements were
performed on a crystalline sample of Fe-gluconate. Fe atoms were revealed to
exist in two phases i.e. a major (90-94 pct.) and a minor (6-10 pct.). Based on
values of spectral parameters the former can be regarded as ferrous and the
latter as ferric. A sub spectrum associated with the ferric phase shows a
significant broadening below ca. 30 K corresponding to 7.5 kGs. A magnetic
origin of the effect was confirmed by the magnetization measurements. Evidence
on the effect of the magnetism on the lattice vibrations of Fe atoms in both
components was found. The Debye temperature, T_D, associated with the
vibrations of Fe2+ ions is by a factor of about 2 smaller in the temperature
range below ca. 30 K than the one determined from the data measured above ca.
30 K. Interestingly, the T_D-value found for the Fe3+ ions from the data
recorded below ca.30 K is about two times smaller than the corresponding value
determined for the Fe2+ ions.
