Temperature evolution of the integrated intensities of the reflection in the orthorhombic phase above 128 K. Below 128 K, the first-order satellites with index and , corresponding to (hkl) ± q, are observed. Below 90 K, a shift in the position of the satellites together with an increase in intensity of the second-order satellites is noticeable. This shift in the position of the reflections corresponds to the change of the wavevector from q = [0, 0, 0.1430 (2)] to q = [0, 0, 0.1247 (2)], while the change in intensity of these satellites is related to changes in the modulation amplitudes. Below 78 K, two single reflections are observed. These two reflections were indexed with the indices and , corresponding to the same diffraction plane belonging to two different twin domains. The inset highlights the region of interest used during the integration.