To fully understand the structure of the layered phase, we first performed PXRD experiments of the product at room temperature and refined the pattern using the Rietveld method (Figure ). The pattern indexed as the R3 � m structure with lattice parameters of a = b = 3.345 (2) Å and c = 16.37 (2) Å. This refinement includes the incorporation of preferred orientation at {104} with a March coefficient of 0.754. The sample contained up to 15% of the cubic ScCx, which we attribute to a relatively low stability of the layered phase. To quantitatively compare the predicted and experimental structures, we further optimized the structure from USPEX using the PBEsol functional. The calculated lattice parameters were 0.45% smaller in a and 0.06% smaller in c, which is less than the typical error between PBEsol and experiment. This further confirms that the synthesized material is layered Sc2C.