To thoroughly probe the crystal symmetry, a full scan of the Ewald-sphere was measured, with integration and data reduction in the monoclinic point group 2/m (corresponding to the C-centred space groups C2/m or C2/c) performed in order to avoid imposing symmetry onto the data. However, there was no evidence of symmetry reduction into the monoclinic system, and so we continued with structure refinement in the orthorhombic crystal system. with the latter report, we find that the Sb-site, nominally lying on the 4c Wyckoff position, is split and disordered above and below the mirror plane at x,y, 1 4 and lies on 8f. This conventional model gave an excellent fit with both the refinement parameters (R 1 = 2.0 %, wR 2 = 4.9 %, GoF = 1.07) and the residual electron density (1.169 > ∆e -/ Å3 > -1.478) suggesting a good agreement between data and model. One drawback, however, is the small difference in the structure factors between the isoelectronic cations Sn 2+ and Sb 3+ , which means that great care has to be taken when comparing the different possible cation ordering motifs that can arise.