Fe1.8Mn0.2P0.9Si0.1 average crystal structure at 300 K, rebuilt from the neutron powder refinement of Thilakan, Ghorai et al., J. Mater. Chem. A 13, 30128 (2025). Hexagonal P-62m, a = 5.9156 Å, c = 3.4553 Å. Fe on tetrahedral 3f (x = 0.25601), Fe/Mn 0.8:0.2 on pyramidal 3g (x = 0.5935), P/Si 0.9:0.1 on 2c and 1b. Site mixing retained from the refinement.