Materials Data on Sm2Pb2O7 by Materials Project
Sm2Pb2O7 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded to seven O2- atoms to form distorted SmO7 pentagonal bipyramids that share corners with two equivalent PbO6 octahedra, corners with two equivalent SmO7 pentagonal bipyramids, corners with two equivalent PbO5 square pyramids, an edgeedge with one PbO6 octahedra, an edgeedge with one SmO7 pentagonal bipyramid, and an edgeedge with one PbO5 square pyramid. The corner-sharing octahedra tilt angles range from 40–53°. There are a spread of Sm–O bond distances ranging from 2.29–2.53 Å. In the second Sm3+ site, Sm3+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Sm–O bond distances ranging from 2.33–2.44 Å. There are two inequivalent Pb4+ sites. In the first Pb4+ site, Pb4+ is bonded to five O2- atoms to form distorted PbO5 square pyramids that share corners with two equivalent PbO6 octahedra, corners with two equivalent SmO7 pentagonal bipyramids, an edgeedge with one PbO6 octahedra, and an edgeedge with one SmO7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 41–44°. There are a spread of Pb–O bond distances ranging from 2.15–2.23 Å. In the second Pb4+ site, Pb4+ is bonded to six O2- atoms to form distorted PbO6 octahedra that share corners with two equivalent SmO7 pentagonal bipyramids, corners with two equivalent PbO5 square pyramids, an edgeedge with one PbO6 octahedra, an edgeedge with one SmO7 pentagonal bipyramid, and an edgeedge with one PbO5 square pyramid. There are a spread of Pb–O bond distances ranging from 2.07–2.43 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted see-saw-like geometry to one Sm3+ and three Pb4+ atoms. In the second O2- site, O2- is bonded to three Sm3+ and one Pb4+ atom to form a mixture of distorted corner and edge-sharing OSm3Pb tetrahedra. In the third O2- site, O2- is bonded in a distorted trigonal non-coplanar geometry to two Sm3+ and one Pb4+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Sm3+ and two Pb4+ atoms. In the fifth O2- site, O2- is bonded in a trigonal planar geometry to two Sm3+ and one Pb4+ atom. In the sixth O2- site, O2- is bonded to three Sm3+ and one Pb4+ atom to form a mixture of distorted corner and edge-sharing OSm3Pb trigonal pyramids. In the seventh O2- site, O2- is bonded in a distorted T-shaped geometry to one Sm3+ and two Pb4+ atoms.