Materials Data on Ca3W2O7 by Materials Project
Ca3W2O7 crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded in a 4-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.36–2.76 Å. In the second Ca2+ site, Ca2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Ca–O bond distances ranging from 2.29–2.70 Å. W4+ is bonded to six O2- atoms to form corner-sharing WO6 octahedra. The corner-sharing octahedra tilt angles range from 32–35°. There are a spread of W–O bond distances ranging from 2.05–2.16 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to three equivalent Ca2+ and one W4+ atom to form distorted corner-sharing OCa3W tetrahedra. In the second O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+ and two equivalent W4+ atoms. In the third O2- site, O2- is bonded in a 5-coordinate geometry to three Ca2+ and two equivalent W4+ atoms. In the fourth O2- site, O2- is bonded to two equivalent Ca2+ and two equivalent W4+ atoms to form distorted corner-sharing OCa2W2 tetrahedra.