  We have recently predicted and subsequently verified experimentally by
specific heat measurements that EuTiO3 undergoes a structural phase transition
at elevated temperature TS = 282 K. The origin of the phase transition has been
attributed to the softening of a transverse acoustic mode stemming from an
oxygen octahedral rotation analogous to SrTiO3. Here we demonstrate that the
theoretical interpretation is correct by using high resolution laboratory X-ray
powder diffraction which evidences a cubic to tetragonal phase transition in
EuTiO3. The room temperature structure could be refined in with a = 3.9082(2)
{\AA} and at 100 K the refinement in the tetragonal space group resulted in a =
5.5192(2) and c = 7.8164(8) {\AA}.
