DOI: 10.17188/1707043
title: Materials Data on K2U(Si2O5)3 by Materials Project

description: K2U(Si2O5)3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.91–3.46 Å. In the second K1+ site, K1+ is bonded in a 3-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.80–3.46 Å. U4+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six SiO4 tetrahedra. There are a spread of U–O bond distances ranging from 2.21–2.30 Å. There are six 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 UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 37°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 28°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 34°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 42°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one UO6 octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 49°. There are a spread of Si–O bond distances ranging from 1.61–1.65 Å. There are fifteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one U4+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two Si4+ atoms. In the fifth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent K1+ and two Si4+ atoms. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to two K1+, one U4+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two Si4+ atoms. In the ninth O2- site, O2- is bonded in a 1-coordinate geometry to two K1+, one U4+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one U4+, and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the twelfth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, one U4+, and one Si4+ atom. In the thirteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fourteenth O2- site, O2- is bonded in a linear geometry to two Si4+ atoms. In the fifteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+, one U4+, and one Si4+ atom.