Materials Data on CaSe2O5 by Materials Project
CaSe2O5 crystallizes in the orthorhombic Pbca space group. The structure is three-dimensional. 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 2.37–2.54 Å. There are two inequivalent Se4+ sites. In the first Se4+ site, Se4+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There are a spread of Se–O bond distances ranging from 1.68–1.92 Å. In the second Se4+ site, Se4+ is bonded in a distorted trigonal non-coplanar geometry to three O2- atoms. There is two shorter (1.70 Å) and one longer (1.85 Å) Se–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to one Ca2+ and one Se4+ atom. In the second O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two equivalent 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 3-coordinate geometry to two equivalent Ca2+ and one Se4+ atom. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Ca2+ and one Se4+ atom.