The Rietveld refinements of 100 K synchrotron diffraction data with the same model as obtained at room temperature showed expected contraction of the unit cell (a = 16.45139( ), b = 9.02912(4), c = 9.02884(6) Å, β = 90.0104(7)°, Figure ) but revealed no ordering transition, and the atomic parameters deviate only slightly from the room temperature solution (Table ).