Residual Cu metal was then removed using further disulfiram (Step 4) (Fig. ), and a final oxidative deintercalation of Li with disulfiram at an elevated temperature (80 °C) produced a new product with the XRD pattern shown in Fig. . Sharp Bragg peaks at 2.01 and 2.84 Å correspond to the a/2 and a/√2 in-plane dimensions of the a = 4 Å square lattice inherited from Sr2MnO2Cu1.5S2, and the sharp peak at 7.92 Å can be assigned to the interlayer spacing between Sr2MnO2 slabs. Other broad peaks in the diffractogram imply the presence of disorder in the stacking of Sr2MnO2S2 slabs. 3D electron diffraction supported severe disorder along the stacking direction with retention of structural integrity within the basal plane (Fig. ). The disorder could not be removed by thermal annealing: decomposition into multiple phases began around 300 °C (Fig. ).