An asymmetrically out-of-plane ordered MAX phase as a precursor for Janus MXenes

, as a candidate precursor for Janus MXenes. We experimentally verified its unique asymmetric ordering through structural characterization. Further atomic-scale analysis via X-ray total scattering and reverse Monte Carlo (RMC) modeling reveals intricate chemical ordering and their possible correlation with atomic displacements. This work provides a pathway for synthesizing Janus MXenes and highlights the structural requirements for achieving symmetry-breaking in MAX phases.