Materials Data on Ca2Se3O8 by Materials Project
Ca2Se3O8 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Ca2+ sites. In the first Ca2+ site, Ca2+ is bonded to seven O2- atoms to form distorted edge-sharing CaO7 pentagonal bipyramids. There are a spread of Ca–O bond distances ranging from 2.33–2.59 Å. In the second Ca2+ site, Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.42–2.67 Å. There are three inequivalent Se4+ sites. In the first Se4+ site, Se4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There is one shorter (1.72 Å) and two longer (1.74 Å) Se–O bond length. In the second Se4+ site, Se4+ is bonded in a trigonal non-coplanar geometry to three O2- atoms. There are a spread of Se–O bond distances ranging from 1.67–1.90 Å. In the third Se4+ site, Se4+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There is two shorter (1.71 Å) and one longer (1.84 Å) Se–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ca2+ and one Se4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two Ca2+ and one Se4+ atom. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to two Se4+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Ca2+ and one Se4+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Ca2+ and one Se4+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ca2+ and one Se4+ atom. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to three Ca2+ and one Se4+ atom. In the eighth O2- site, O2- is bonded to three Ca2+ and one Se4+ atom to form distorted edge-sharing OCa3Se tetrahedra.