Materials Data on KEu2Si4O10F by Materials Project

Abstract

KEu2Si4O10F crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. K1+ is bonded in a 9-coordinate geometry to eight O2- and one F1- atom. There are a spread of K–O bond distances ranging from 2.74–3.44 Å. The K–F bond length is 3.21 Å. There are two inequivalent Eu2+ sites. In the first Eu2+ site, Eu2+ is bonded in a 8-coordinate geometry to six O2- and two equivalent F1- atoms. There are a spread of Eu–O bond distances ranging from 2.54–3.00 Å. There are one shorter (2.43 Å) and one longer (2.70 Å) Eu–F bond lengths. In the second Eu2+ site, Eu2+ is bonded to five O2- and one F1- atom to form distorted EuO5F octahedra that share corners with five SiO4 tetrahedra and an edgeedge with one EuO5F octahedra. There are a spread of Eu–O bond distances ranging from 2.52–2.63 Å. The Eu–F bond length is 2.44 Å. There are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent EuO5F octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 57–64°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one EuO5F octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 54°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one EuO5F octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 45°. There are a spread of Si–O bond distances ranging from 1.60–1.67 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one EuO5F octahedra and corners with three SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 64°. There are a spread of Si–O bond distances ranging from 1.60–1.66 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one K1+ and two Si4+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Eu2+ and two Si4+ atoms. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one K1+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to three Eu2+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent K1+ and two Si4+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+ and two Si4+ atoms. In the seventh O2- site, O2- is bonded in a bent 120 degrees geometry to one K1+ and two Si4+ atoms. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to three Eu2+ and one Si4+ atom. In the ninth O2- site, O2- is bonded in a distorted tetrahedral geometry to one K1+, two Eu2+, and one Si4+ atom. In the tenth O2- site, O2- is bonded in a distorted single-bond geometry to one K1+, two Eu2+, and one Si4+ atom. F1- is bonded in a 3-coordinate geometry to one K1+ and three Eu2+ atoms.