DOI: 10.17188/1287665
title: Materials Data on CaU2Si2H12O17 by Materials Project

description: CaU2Si2(H5O8)2H2O crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional and consists of two water molecules and one CaU2Si2(H5O8)2 framework. In the CaU2Si2(H5O8)2 framework, Ca2+ is bonded to seven O2- atoms to form CaO7 pentagonal bipyramids that share corners with two UO7 pentagonal bipyramids and a cornercorner with one SiO4 tetrahedra. There are a spread of Ca–O bond distances ranging from 2.37–2.49 Å. There are two inequivalent U6+ sites. In the first U6+ site, U6+ is bonded to seven O2- atoms to form distorted UO7 pentagonal bipyramids that share a cornercorner with one CaO7 pentagonal bipyramid, corners with three equivalent SiO4 tetrahedra, edges with two equivalent UO7 pentagonal bipyramids, and an edgeedge with one SiO4 tetrahedra. There are a spread of U–O bond distances ranging from 1.85–2.49 Å. In the second U6+ site, U6+ is bonded to seven O2- atoms to form distorted UO7 pentagonal bipyramids that share a cornercorner with one CaO7 pentagonal bipyramid, corners with three equivalent SiO4 tetrahedra, edges with two equivalent UO7 pentagonal bipyramids, and an edgeedge with one SiO4 tetrahedra. There are a spread of U–O bond distances ranging from 1.85–2.50 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one CaO7 pentagonal bipyramid, corners with three equivalent UO7 pentagonal bipyramids, and an edgeedge with one UO7 pentagonal bipyramid. There are a spread of Si–O bond distances ranging from 1.63–1.67 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with three equivalent UO7 pentagonal bipyramids and an edgeedge with one UO7 pentagonal bipyramid. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. There are ten 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 1.00 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the fifth 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 sixth 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 seventh H1+ site, H1+ is bonded in a single-bond geometry to two O2- atoms. There is one shorter (1.00 Å) and one longer (1.72 Å) H–O bond length. In the eighth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the ninth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. In the tenth H1+ site, H1+ is bonded in a single-bond geometry to one O2- atom. The H–O bond length is 0.99 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to one U6+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ca2+ and one U6+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Ca2+ and one U6+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to one U6+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent U6+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent U6+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent U6+ and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent U6+ and one Si4+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U6+ and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to one U6+, one Si4+, and one H1+ atom. In the eleventh O2- site, O2- is bonded in a 2-coordinate geometry to one Ca2+, one Si4+, and one H1+ atom. In the twelfth O2- site, O2- is bonded in a bent 120 degrees geometry to one Si4+ and one H1+ atom. In the thirteenth O2- site, O2- is bonded in a distorted water-like geometry to one Ca2+ and two H1+ atoms. In the fourteenth O2- site, O2- is bonded in a water-like geometry to one Ca2+ and two H1+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted water-like geometry to one Ca2+ and two H1+ atoms. In the sixteenth O2- site, O2- is bonded in a water-like geometry to one Ca2+ and two H1+ atoms.