DOI: 10.17188/1704570
title: Materials Data on NaCaZrFeSi2O8F by Materials Project

description: NaCaZrFeSi2O8F is Esseneite-derived structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Na1+ is bonded in a 6-coordinate geometry to four O2- and two equivalent F1- atoms. There are a spread of Na–O bond distances ranging from 2.44–2.66 Å. There are one shorter (2.27 Å) and one longer (2.37 Å) Na–F bond lengths. Ca2+ is bonded in a 8-coordinate geometry to seven O2- and one F1- atom. There are a spread of Ca–O bond distances ranging from 2.34–2.88 Å. The Ca–F bond length is 2.22 Å. Zr4+ is bonded to six O2- atoms to form ZrO6 octahedra that share corners with two equivalent FeO5F octahedra, corners with five SiO4 tetrahedra, and an edgeedge with one FeO5F octahedra. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Zr–O bond distances ranging from 1.98–2.34 Å. Fe2+ is bonded to five O2- and one F1- atom to form FeO5F octahedra that share corners with two equivalent ZrO6 octahedra, corners with three SiO4 tetrahedra, an edgeedge with one ZrO6 octahedra, and an edgeedge with one FeO5F octahedra. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Fe–O bond distances ranging from 2.12–2.40 Å. The Fe–F bond length is 2.33 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 corners with two equivalent ZrO6 octahedra, corners with two equivalent FeO5F octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 44–66°. There are a spread of Si–O bond distances ranging from 1.62–1.65 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one FeO5F octahedra, corners with three equivalent ZrO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–55°. There are a spread of Si–O bond distances ranging from 1.62–1.65 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Zr4+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Ca2+, one Zr4+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Zr4+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a linear geometry to two equivalent Ca2+ and two Si4+ atoms. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, one Ca2+, one Fe2+, and one Si4+ atom. In the sixth O2- site, O2- is bonded to one Na1+, one Zr4+, and two equivalent Fe2+ atoms to form distorted ONaZrFe2 tetrahedra that share corners with two equivalent FNa2CaFe tetrahedra, an edgeedge with one ONaZrFe2 tetrahedra, and an edgeedge with one FNa2CaFe tetrahedra. In the seventh O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Zr4+, one Fe2+, and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, one Zr4+, one Fe2+, and one Si4+ atom. F1- is bonded to two equivalent Na1+, one Ca2+, and one Fe2+ atom to form distorted FNa2CaFe tetrahedra that share corners with two equivalent ONaZrFe2 tetrahedra, an edgeedge with one ONaZrFe2 tetrahedra, and an edgeedge with one FNa2CaFe tetrahedra.