Extended Data Fig. 2: Atomic arrangement of magnetite and iron nitride (Fe4N).

a. Crystal structure of magnetite from the view along the c-axis. Red and brown circles indicate oxygen and iron atoms in magnetite, respectively. b. Atomic arrangement of iron in magnetite. Iron atoms in tetrahedral sites are indicated by cyan circles. Distance between the (200) plane (2.099 Å) of magnetite is shown. c. Crystal structure of Fe₄N from the view along the c-axis. Distance between the (100) plane of Fe₄N (1.895–1.94 Å) are measured values from the cubic crystals on space-weathered magnetite in A0104-026006 and A0104-028098. These schematic images were made using the Recipro software (Seto, Y. & Ohtsuka, M, 2022)¹⁷.