Materials Data on Sr2CaTi3O9 by Materials Project

Abstract

Sr2CaTi3O9 is (Cubic) Perovskite-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Sr2+ is bonded to twelve O2- atoms to form SrO12 cuboctahedra that share corners with four equivalent CaO12 cuboctahedra, corners with eight equivalent SrO12 cuboctahedra, a faceface with one CaO12 cuboctahedra, faces with five equivalent SrO12 cuboctahedra, and faces with eight TiO6 octahedra. There are eight shorter (2.78 Å) and four longer (2.79 Å) Sr–O bond lengths. Ca2+ is bonded to twelve O2- atoms to form CaO12 cuboctahedra that share corners with four equivalent CaO12 cuboctahedra, corners with eight equivalent SrO12 cuboctahedra, faces with two equivalent SrO12 cuboctahedra, faces with four equivalent CaO12 cuboctahedra, and faces with eight equivalent TiO6 octahedra. There are eight shorter (2.77 Å) and four longer (2.78 Å) Ca–O bond lengths. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six TiO6 octahedra, faces with four equivalent SrO12 cuboctahedra, and faces with four equivalent CaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Ti–O bond distances ranging from 1.95–1.97 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six TiO6 octahedra and faces with eight equivalent SrO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. There is four shorter (1.96 Å) and two longer (1.97 Å) Ti–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to two equivalent Sr2+, two equivalent Ca2+, and two equivalent Ti4+ atoms. In the second O2- site, O2- is bonded in a distorted linear geometry to four equivalent Sr2+ and two equivalent Ti4+ atoms. In the third O2- site, O2- is bonded in a distorted linear geometry to four equivalent Ca2+ and two equivalent Ti4+ atoms. In the fourth O2- site, O2- is bonded in a distorted linear geometry to four equivalent Sr2+ and two Ti4+ atoms.