“…Moreover, reduced SBN (SrxBa1−xNb2O6−δ) is reported to have promising thermoelectric properties 14 and filled SBN (SrxBa1.2-xNb2O6) is reported to show low temperature superconductivity 15 .The crystal structure of SBN consists of corner-sharing NbO6 octahedra forming triangular C-sites (empty in SBN), square A1sites and pentagonal A2-sites 6,16 filled with a total of 5 alkaline earth atoms, and 1 vacancy, as shown in Figure 1. The average structure is described by the P4bm space group, but a better understanding of the link between order/disorder, polarization and incommensurate tilting of NbO6 octahedra in the structure is still being addressed 16,17 . The three species, ((5-x)*Sr 2+ , x*Ba 2+ and one vacancy) are distributed on a total of 6 sites per unit cell (2 A1-and 4 A2-sites), and one X-ray diffraction experiment is not sufficient to determine the occupancy of Ba 2+ , Sr 2+ and the vacancy on the two sites due to parameter correlations 18 .…”