Materials Data on NaCaTiMnSi2O8F by Materials Project

Abstract

NaCaTiMnSi2O8F 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 2.40–2.54 Å. There are one shorter (2.26 Å) and one longer (2.38 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 2.30–2.82 Å. The Ca–F bond length is 2.23 Å. Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share corners with two equivalent MnO5F octahedra, corners with five SiO4 tetrahedra, and an edgeedge with one MnO5F octahedra. The corner-sharing octahedra tilt angles range from 52–54°. There are a spread of Ti–O bond distances ranging from 1.78–2.35 Å. Mn2+ is bonded to five O2- and one F1- atom to form MnO5F octahedra that share corners with two equivalent TiO6 octahedra, corners with three SiO4 tetrahedra, an edgeedge with one TiO6 octahedra, and an edgeedge with one MnO5F octahedra. The corner-sharing octahedra tilt angles range from 52–54°. There are a spread of Mn–O bond distances ranging from 2.14–2.34 Å. The Mn–F bond length is 2.23 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 MnO5F octahedra, corners with three equivalent TiO6 octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 37–56°. There are a spread of Si–O bond distances ranging from 1.62–1.66 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent TiO6 octahedra, corners with two equivalent MnO5F octahedra, and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedra tilt angles range from 42–68°. There are a spread of Si–O bond distances ranging from 1.61–1.66 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Na1+, one Ti4+, and two equivalent Mn2+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Ti4+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Ca2+, one Ti4+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Ca2+, one Ti4+, one Mn2+, and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Ti4+, one Mn2+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Ca2+, one Ti4+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a distorted linear geometry to two equivalent Ca2+ and two Si4+ atoms. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, one Ca2+, one Mn2+, and one Si4+ atom. F1- is bonded to two equivalent Na1+, one Ca2+, and one Mn2+ atom to form distorted edge-sharing FNa2CaMn tetrahedra.