Instead of allowing each Sr2MnO2S2 slab to slide freely, we also attempted two other approaches that constructed large supercells by piling up the pre-defined "collapsed" disulphide layers and Sr2MnO2Cu1.5S2-like layers (See Fig. -16 for further discussion). Although these approaches did not give better fitting than Fig. , they gave the qualitative idea that both types of the layers co-existed with significant amounts and in various stacking sequence. This point is revisited later in the article with our microscopy and spectroscopic analyses. for the refined parameters), S-S distances shortened further down to 2.18-2.21 Å. These values are comparable to the 2.13 Å and 2.16 Å in BaS2 and FeS2 respectively suggesting S-S dimers are present in the "collapsed" phase derived from sulfide oxidation. This was supported by spectroscopic evidence. Fig. -b compare XANES spectra of Sr2MnO2Cu1.5S2 and its "collapsed" derivative. The Mn K-edge absorption in the "collapsed" phase increased in energy by only 0.2 eV (Edges in MnO and Mn2O3 differ by 4 eV), and was even smaller than the 0.6 eV shift on partial Cu deintercalation to Sr2MnO2Cu1.33S2. A Curie-Weiss fit to the magnetic susceptibility (Fig. ) of the "collapsed" phase produced an effective moment μeff of 5.67(1) μB, similar to Sr2MnO2Cu1.5S2, consistent with retention of a mean Mn oxidation state of +2.5.