300°C 500°C 700°C 900°C ; the evolution of this layered phase is tracked only once it has formed and slightly crystallized after 400 ºC. Parameters dependent on oxygen z position are reported starting even later, to ensure reliability of the refinement. We highlight the near invariance of the structure during the high temperature hold, shown in greater detail in f)-h). In particular, changes associated with increasing antisite defects -decreasing c lattice parameter and c/a ratio, and convergent TM-O and Li-O slab heights -are observable but small during the high temperature hold.