Materials Data on NaCa3Fe(SiO3)8 by Materials Project

Abstract

NaCa3Fe(SiO3)8 crystallizes in the monoclinic P2 space group. The structure is three-dimensional. Na is bonded in a 8-coordinate geometry to eight O atoms. There are a spread of Na–O bond distances ranging from 2.27–2.78 Å. There are three inequivalent Ca sites. In the first Ca site, Ca is bonded in a 4-coordinate geometry to four O atoms. There are two shorter (2.31 Å) and two longer (2.34 Å) Ca–O bond lengths. In the second Ca site, Ca is bonded in a 4-coordinate geometry to four O atoms. There are two shorter (2.26 Å) and two longer (2.39 Å) Ca–O bond lengths. In the third Ca site, Ca is bonded in a 4-coordinate geometry to six O atoms. There are a spread of Ca–O bond distances ranging from 2.25–2.91 Å. Fe is bonded to six O atoms to form FeO6 octahedra that share corners with six SiO4 tetrahedra. There are a spread of Fe–O bond distances ranging from 1.86–1.96 Å. There are four inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one FeO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 36°. There are a spread of Si–O bond distances ranging from 1.63–1.66 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one FeO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 48°. There are a spread of Si–O bond distances ranging from 1.62–1.68 Å. In the third Si site, Si is bonded to four O atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.63–1.67 Å. In the fourth Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one FeO6 octahedra and corners with two equivalent SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 53°. There are a spread of Si–O bond distances ranging from 1.63–1.67 Å. There are twelve inequivalent O sites. In the first O site, O is bonded in a distorted bent 120 degrees geometry to one Ca and one Si atom. In the second O site, O is bonded in a distorted trigonal planar geometry to one Ca, one Fe, and one Si atom. In the third O site, O is bonded in a bent 150 degrees geometry to one Ca and one Si atom. In the fourth O site, O is bonded in a 3-coordinate geometry to one Na, one Fe, and one Si atom. In the fifth O site, O is bonded in a distorted T-shaped geometry to one Na, one Fe, and one Si atom. In the sixth O site, O is bonded in a distorted water-like geometry to one Ca and one Si atom. In the seventh O site, O is bonded in a water-like geometry to one Ca and one Si atom. In the eighth O site, O is bonded in a water-like geometry to one Ca and one Si atom. In the ninth O site, O is bonded in a distorted bent 150 degrees geometry to one Na and two Si atoms. In the tenth O site, O is bonded in a distorted bent 150 degrees geometry to two Si atoms. In the eleventh O site, O is bonded in a distorted bent 150 degrees geometry to one Na and two Si atoms. In the twelfth O site, O is bonded in a distorted bent 120 degrees geometry to one Ca and two Si atoms.