DOE OSTI2020
YZr5Si5PO24 is Zircon-derived structured and crystallizes in the orthorhombic C222 space group. The structure is three-dimensional. Y3+ is bonded to eight O2- atoms to form distorted YO8 hexagonal bipyramids that share corners with four SiO4 tetrahedra and edges with two equivalent PO4 tetrahedra. There are a spread of Y–O bond distances ranging from 2.27–2.39 Å. There are six inequivalent Zr4+ sites. In the first Zr4+ site, Zr4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are four shorter (2.24 Å) and four longer (2.27 Å) Zr–O bond lengths. In the second Zr4+ site, Zr4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Zr–O bond distances ranging from 2.15–2.30 Å. In the third Zr4+ site, Zr4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Zr–O bond distances ranging from 2.17–2.28 Å. In the fourth Zr4+ site, Zr4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are four shorter (2.18 Å) and four longer (2.29 Å) Zr–O bond lengths. In the fifth Zr4+ site, Zr4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Zr–O bond distances ranging from 2.15–2.29 Å. In the sixth Zr4+ site, Zr4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Zr–O bond distances ranging from 2.17–2.29 Å. There are six inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four equivalent O2- atoms to form distorted SiO4 tetrahedra that share corners with four equivalent YO8 hexagonal bipyramids. All Si–O bond lengths are 1.65 Å. In the second Si4+ site, Si4+ is bonded in a tetrahedral geometry to four O2- atoms. All Si–O bond lengths are 1.64 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent YO8 hexagonal bipyramids. There is two shorter (1.64 Å) and two longer (1.65 Å) Si–O bond length. In the fourth Si4+ site, Si4+ is bonded in a tetrahedral geometry to four O2- atoms. All Si–O bond lengths are 1.64 Å. In the fifth Si4+ site, Si4+ is bonded in a tetrahedral geometry to four O2- atoms. All Si–O bond lengths are 1.64 Å. In the sixth Si4+ site, Si4+ is bonded in a tetrahedral geometry to four equivalent O2- atoms. All Si–O bond lengths are 1.64 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share edges with two equivalent YO8 hexagonal bipyramids. All P–O bond lengths are 1.55 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to one Y3+, one Zr4+, and one P5+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to one Y3+, one Zr4+, and one P5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to one Y3+, one Zr4+, and one Si4+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Zr4+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to two Zr4+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to two Zr4+ and one Si4+ atom. In the seventh O2- site, O2- is bonded in a 3-coordinate geometry to two Zr4+ and one Si4+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Y3+, one Zr4+, and one Si4+ atom. In the ninth O2- site, O2- is bonded in a 3-coordinate geometry to two Zr4+ and one Si4+ atom. In the tenth O2- site, O2- is bonded in a 3-coordinate geometry to two Zr4+ and one Si4+ atom. In the eleventh O2- site, O2- is bonded in a 3-coordinate geometry to two Zr4+ and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to two Zr4+ and one Si4+ atom.