Materials Data on YScSi2O7 by Materials Project
YScSi2O7 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. Y3+ is bonded to six O2- atoms to form distorted YO6 pentagonal pyramids that share corners with six equivalent SiO4 tetrahedra and edges with three equivalent ScO6 octahedra. There are four shorter (2.24 Å) and two longer (2.40 Å) Y–O bond lengths. Sc3+ is bonded to six O2- atoms to form distorted ScO6 octahedra that share corners with six equivalent SiO4 tetrahedra and edges with three equivalent YO6 pentagonal pyramids. There are a spread of Sc–O bond distances ranging from 2.13–2.16 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent ScO6 octahedra, corners with three equivalent YO6 pentagonal pyramids, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 42–53°. There is one shorter (1.64 Å) and three longer (1.65 Å) Si–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to one Y3+, one Sc3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to one Y3+, one Sc3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Y3+, one Sc3+, and one Si4+ atom.