Materials Data on Sc2Si2O7 by Materials Project

Abstract

Sc2Si2O7 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Sc3+ is bonded to eight O2- atoms to form distorted ScO8 hexagonal bipyramids that share edges with six equivalent ScO8 hexagonal bipyramids and edges with six equivalent SiO6 octahedra. There are two shorter (2.03 Å) and six longer (2.34 Å) Sc–O bond lengths. Si4+ is bonded to six equivalent O2- atoms to form SiO6 octahedra that share corners with six equivalent SiO6 octahedra and edges with six equivalent ScO8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 46°. All Si–O bond lengths are 1.80 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Sc3+ and two equivalent Si4+ atoms. In the second O2- site, O2- is bonded to four equivalent Sc3+ atoms to form corner-sharing OSc4 tetrahedra.