| Abstract: | The continuous variations of reflexion intensities and lattice spacings are observed for the transformation from mackinawite. FeS (tetragonal), to greigite, Fe3S4 (cubic). by electron beam heating. At the beginning of the transformation, the (222) reflexion of greigite appears. At the end, the (400) and (220) reflexions of greigite are stronger than those so far reported, and the (311), (422) and (331) reflexions are weaker. The observations suggest, that the (101) plane of mackinawite changes to the (222) plane of greigite. The transformation proceeds by bulk diffusion of sulfur, which initially existed in an amorphous state on the surface of mackinawite. |
