Materials Data on Nd3Ti3(SeO4)2 by Materials Project

Abstract

Nd3Ti3O8Se2 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are three inequivalent Nd+2.67+ sites. In the first Nd+2.67+ site, Nd+2.67+ is bonded in a 4-coordinate geometry to four Se2- and four O2- atoms. All Nd–Se bond lengths are 3.10 Å. There are a spread of Nd–O bond distances ranging from 2.43–2.45 Å. In the second Nd+2.67+ site, Nd+2.67+ is bonded in a 9-coordinate geometry to two equivalent Se2- and seven O2- atoms. Both Nd–Se bond lengths are 3.06 Å. There are a spread of Nd–O bond distances ranging from 2.44–2.61 Å. In the third Nd+2.67+ site, Nd+2.67+ is bonded in a 7-coordinate geometry to four Se2- and three O2- atoms. There are a spread of Nd–Se bond distances ranging from 3.03–3.14 Å. There are two shorter (2.33 Å) and one longer (2.46 Å) Nd–O bond lengths. There are three inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with two equivalent TiO6 octahedra, edges with two equivalent TiO6 octahedra, and an edgeedge with one TiSeO5 trigonal bipyramid. The corner-sharing octahedral tilt angles are 23°. There are a spread of Ti–O bond distances ranging from 1.95–2.10 Å. In the second Ti4+ site, Ti4+ is bonded to one Se2- and five O2- atoms to form distorted TiSeO5 trigonal bipyramids that share corners with two equivalent TiSeO5 trigonal bipyramids and an edgeedge with one TiO6 octahedra. The Ti–Se bond length is 3.05 Å. There are a spread of Ti–O bond distances ranging from 1.82–2.04 Å. In the third Ti4+ site, Ti4+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Ti–O bond distances ranging from 1.80–2.02 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to five Nd+2.67+ atoms to form distorted SeNd5 square pyramids that share corners with four equivalent ONd3Ti tetrahedra, edges with four equivalent SeNd5 square pyramids, and an edgeedge with one ONd3Ti tetrahedra. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to five Nd+2.67+, one Ti4+, and two equivalent O2- atoms. Both Se–O bond lengths are 3.34 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Nd+2.67+ and two Ti4+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Nd+2.67+, one Ti4+, and two equivalent Se2- atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three equivalent Nd+2.67+ and one Ti4+ atom. In the fourth O2- site, O2- is bonded to three equivalent Nd+2.67+ and one Ti4+ atom to form distorted ONd3Ti tetrahedra that share corners with four equivalent SeNd5 square pyramids, corners with two equivalent ONd3Ti tetrahedra, an edgeedge with one SeNd5 square pyramid, and edges with two equivalent ONd3Ti tetrahedra. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to one Nd+2.67+ and three Ti4+ atoms. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two Nd+2.67+ and two equivalent Ti4+ atoms. In the seventh O2- site, O2- is bonded in a distorted see-saw-like geometry to four Ti4+ atoms. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent Nd+2.67+ and two Ti4+ atoms.