Materials Data on CaH4Se2O9 by Materials Project
CaH4Se2O9 crystallizes in the monoclinic P2_1/c space group. The structure is one-dimensional and consists of two CaH4Se2O9 ribbons oriented in the (1, 0, 0) direction. Ca2+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Ca–O bond distances ranging from 2.37–2.90 Å. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.02 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 1.00 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.98 Å. There are two inequivalent Se6+ sites. In the first Se6+ site, Se6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Se–O bond distances ranging from 1.65–1.75 Å. In the second Se6+ site, Se6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Se–O bond distances ranging from 1.64–1.76 Å. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Ca2+ and one Se6+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ca2+ and one Se6+ atom. In the third O2- site, O2- is bonded in a distorted water-like geometry to one H1+ and one Se6+ atom. In the fourth O2- site, O2- is bonded in a water-like geometry to one Ca2+ and one Se6+ atom. In the fifth O2- site, O2- is bonded in a water-like geometry to one Ca2+ and two H1+ atoms. In the sixth O2- site, O2- is bonded in a bent 120 degrees geometry to one Ca2+ and one Se6+ atom. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Ca2+ and one Se6+ atom. In the eighth O2- site, O2- is bonded in a distorted water-like geometry to one H1+ and one Se6+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Ca2+ and one Se6+ atom.