Materials Data on La2Nb2N2O5 by Materials Project

Abstract

La2Nb2N2O5 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are two inequivalent La3+ sites. In the first La3+ site, La3+ is bonded to two N3- and six O2- atoms to form distorted LaN2O6 hexagonal bipyramids that share edges with six LaN2O6 hexagonal bipyramids and edges with six NbN2O4 octahedra. There are one shorter (2.29 Å) and one longer (2.75 Å) La–N bond lengths. There are a spread of La–O bond distances ranging from 2.36–2.73 Å. In the second La3+ site, La3+ is bonded to three N3- and five O2- atoms to form distorted LaN3O5 hexagonal bipyramids that share edges with six LaN2O6 hexagonal bipyramids and edges with six NbN2O4 octahedra. There are a spread of La–N bond distances ranging from 2.31–2.77 Å. There are a spread of La–O bond distances ranging from 2.37–2.71 Å. There are two inequivalent Nb5+ sites. In the first Nb5+ site, Nb5+ is bonded to one N3- and five O2- atoms to form NbNO5 octahedra that share corners with six NbNO5 octahedra and edges with six LaN2O6 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 39–48°. The Nb–N bond length is 1.93 Å. There are a spread of Nb–O bond distances ranging from 2.03–2.18 Å. In the second Nb5+ site, Nb5+ is bonded to two N3- and four O2- atoms to form NbN2O4 octahedra that share corners with six NbNO5 octahedra and edges with six LaN2O6 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 40–49°. There is one shorter (1.97 Å) and one longer (2.02 Å) Nb–N bond length. There are a spread of Nb–O bond distances ranging from 2.06–2.15 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a 2-coordinate geometry to two La3+ and two Nb5+ atoms. In the second N3- site, N3- is bonded in a 2-coordinate geometry to two equivalent La3+ and two equivalent Nb5+ atoms. In the third N3- site, N3- is bonded to four La3+ atoms to form NLa4 tetrahedra that share corners with four equivalent OLa4 tetrahedra. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two La3+ and two Nb5+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent La3+ and two equivalent Nb5+ atoms. In the third O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent La3+ and two equivalent Nb5+ atoms. In the fourth O2- site, O2- is bonded to four La3+ atoms to form OLa4 tetrahedra that share corners with four equivalent NLa4 tetrahedra. In the fifth O2- site, O2- is bonded in a 4-coordinate geometry to two La3+ and two Nb5+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two La3+ and two Nb5+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two equivalent La3+ and two equivalent Nb5+ atoms.