Materials Data on Na5Eu4Si4O16F by Materials Project

Abstract

Na5Eu4Si4O16F crystallizes in the tetragonal I-4 space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.43–2.90 Å. In the second Na1+ site, Na1+ is bonded in a distorted q6 geometry to eight O2- and two equivalent F1- atoms. There are four shorter (2.66 Å) and four longer (2.89 Å) Na–O bond lengths. Both Na–F bond lengths are 2.77 Å. Eu3+ is bonded in a 8-coordinate geometry to seven O2- and one F1- atom. There are a spread of Eu–O bond distances ranging from 2.34–2.63 Å. The Eu–F bond length is 2.57 Å. Si4+ is bonded in a tetrahedral geometry to four O2- atoms. There is three shorter (1.64 Å) and one longer (1.66 Å) Si–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, two equivalent Eu3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, two equivalent Eu3+, and one Si4+ atom. In the third O2- site, O2- is bonded in a 6-coordinate geometry to four equivalent Na1+, one Eu3+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, two equivalent Eu3+, and one Si4+ atom. F1- is bonded to two equivalent Na1+ and four equivalent Eu3+ atoms to form distorted corner-sharing FNa2Eu4 octahedra. The corner-sharing octahedral tilt angles are 0°.