DOE OSTI2020
Sm2Sc2O5 is Ilmenite-like structured and crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are two inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Sm–O bond distances ranging from 2.32–2.68 Å. In the second Sm3+ site, Sm3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Sm–O bond distances ranging from 2.32–2.69 Å. There are two inequivalent Sc2+ sites. In the first Sc2+ site, Sc2+ is bonded to six O2- atoms to form ScO6 octahedra that share corners with four equivalent ScO6 octahedra and corners with two equivalent ScO4 trigonal pyramids. The corner-sharing octahedral tilt angles are 38°. There are a spread of Sc–O bond distances ranging from 2.09–2.15 Å. In the second Sc2+ site, Sc2+ is bonded to four O2- atoms to form ScO4 trigonal pyramids that share corners with two equivalent ScO6 octahedra and corners with two equivalent ScO4 trigonal pyramids. The corner-sharing octahedra tilt angles range from 35–36°. There are a spread of Sc–O bond distances ranging from 2.06–2.18 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Sm3+ and two equivalent Sc2+ atoms to form distorted OSm2Sc2 tetrahedra that share corners with two equivalent OSm4Sc2 octahedra, corners with four equivalent OSm2Sc2 tetrahedra, an edgeedge with one OSm4Sc2 octahedra, and edges with two equivalent OSm2Sc2 tetrahedra. The corner-sharing octahedra tilt angles range from 61–62°. In the second O2- site, O2- is bonded to two equivalent Sm3+ and two equivalent Sc2+ atoms to form distorted OSm2Sc2 tetrahedra that share corners with two equivalent OSm4Sc2 octahedra, corners with four equivalent OSm2Sc2 tetrahedra, an edgeedge with one OSm4Sc2 octahedra, and edges with two equivalent OSm2Sc2 tetrahedra. The corner-sharing octahedral tilt angles are 62°. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Sm3+ and two Sc2+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Sm3+ and two Sc2+ atoms. In the fifth O2- site, O2- is bonded to four Sm3+ and two equivalent Sc2+ atoms to form distorted OSm4Sc2 octahedra that share corners with four OSm2Sc2 tetrahedra, edges with two OSm2Sc2 tetrahedra, and faces with two equivalent OSm4Sc2 octahedra.