Etude cristallographique du systeme FeSSc2S3 preparations et structures de FeSc2S4 et Fe0.85Sc2.10S4

The crystal structures of FeSc2S4 and Fe0.85Sc2.10S4 have been determined by three dimensional X-ray diffraction. The cubic cells, space group Fd3m, have lattice constants a = 10,501 Å for FeSc2S4 and a = 10,444 Å for Fe0.85Sc2.10S4. Iron is divalent and scandium trivalent. FeSc2S4 is a direct spinel structure, Fe0.85Sc2.10S4 is near a spinel structure. Only 0,5 iron atom is on every 8a position; 0,175 Fe and 1,05 Sc lie on octahedral 16d and 16c site.