  We report on a single-crystal X-ray structure study of $GdFe_{3}(BO_{3})_{4}$
at room temperature and at T=90 K. At room temperature $GdFe_{3}(BO_{3})_{4}$
crystallizes in a trigonal space group R32 (No. 155), the same as found for
other members of iron-borate family $RFe_{3}(BO_{3})_{4}$. At 90 K the
structure of $GdFe_{3}(BO_{3})_{4}$ has transformed to the space group
$P3_{1}2_{1}$ (No. 152). The low-temperature structure determination gives new
insight into the weakly first-order structural phase transition at 156 K and
into the related Raman phonon anomalies. The discovery of two inequivalent iron
chains in the low temperature structure provide new point of view on the
low-temperature magnetic properties.
