Materials Data on Na5Y4Si4O16F by Materials Project
Na5Y4(SiO4)4F 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 2.37–2.88 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 (2.59 Å) and four longer (2.82 Å) Na–O bond lengths. Both Na–F bond lengths are 2.73 Å. Y3+ is bonded in a 8-coordinate geometry to seven O2- and one F1- atom. There are a spread of Y–O bond distances ranging from 2.29–2.54 Å. The Y–F bond length is 2.53 Å. Si4+ is bonded in a tetrahedral geometry to four O2- atoms. There is one shorter (1.64 Å) and three longer (1.65 Å) Si–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to four equivalent Na1+, one Y3+, and one Si4+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, two equivalent Y3+, one Si4+, and one F1- atom. The O–F bond length is 2.78 Å. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two Na1+, two equivalent Y3+, one Si4+, and one F1- atom. The O–F bond length is 2.68 Å. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Na1+, two equivalent Y3+, and one Si4+ atom. F1- is bonded in a 6-coordinate geometry to two equivalent Na1+, four equivalent Y3+, and eight O2- atoms.