DOE OSTI2020
Nd2(BiO2)7 crystallizes in the monoclinic Cm space group. The structure is two-dimensional and consists of one Nd2(BiO2)7 sheet oriented in the (0, 0, 1) direction. there are two inequivalent Nd+2.50+ sites. In the first Nd+2.50+ site, Nd+2.50+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Nd–O bond distances ranging from 2.47–2.65 Å. In the second Nd+2.50+ site, Nd+2.50+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Nd–O bond distances ranging from 2.39–2.60 Å. There are seven inequivalent Bi+3.29+ sites. In the first Bi+3.29+ site, Bi+3.29+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Bi–O bond distances ranging from 2.29–2.64 Å. In the second Bi+3.29+ site, Bi+3.29+ is bonded to five O2- atoms to form distorted edge-sharing BiO5 square pyramids. There are a spread of Bi–O bond distances ranging from 2.12–2.47 Å. In the third Bi+3.29+ site, Bi+3.29+ is bonded to five O2- atoms to form distorted BiO5 trigonal bipyramids that share corners with two equivalent BiO5 square pyramids, corners with two equivalent BiO4 tetrahedra, and corners with two equivalent BiO5 trigonal bipyramids. There are a spread of Bi–O bond distances ranging from 2.14–2.58 Å. In the fourth Bi+3.29+ site, Bi+3.29+ is bonded to four O2- atoms to form distorted BiO4 tetrahedra that share corners with two equivalent BiO5 square pyramids, corners with two equivalent BiO4 tetrahedra, and corners with two equivalent BiO5 trigonal bipyramids. There are a spread of Bi–O bond distances ranging from 2.18–2.26 Å. In the fifth Bi+3.29+ site, Bi+3.29+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.19–2.78 Å. In the sixth Bi+3.29+ site, Bi+3.29+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Bi–O bond distances ranging from 2.20–2.63 Å. In the seventh Bi+3.29+ site, Bi+3.29+ is bonded to five O2- atoms to form distorted BiO5 square pyramids that share corners with two equivalent BiO4 tetrahedra, corners with two equivalent BiO5 trigonal bipyramids, and edges with two equivalent BiO5 square pyramids. There are a spread of Bi–O bond distances ranging from 2.12–2.45 Å. There are fourteen inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Nd+2.50+ and two Bi+3.29+ atoms to form distorted ONd2Bi2 tetrahedra that share corners with twelve ONd2Bi2 tetrahedra, edges with three ONdBi3 tetrahedra, and edges with two equivalent ONdBi3 trigonal pyramids. In the second O2- site, O2- is bonded in a trigonal planar geometry to three Bi+3.29+ atoms. In the third O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent Bi+3.29+ atoms. In the fourth O2- site, O2- is bonded to one Nd+2.50+ and three Bi+3.29+ atoms to form distorted ONdBi3 tetrahedra that share corners with seven ONd2Bi2 tetrahedra, a cornercorner with one ONdBi3 trigonal pyramid, and edges with three ONdBi3 tetrahedra. In the fifth O2- site, O2- is bonded to one Nd+2.50+ and three Bi+3.29+ atoms to form distorted ONdBi3 tetrahedra that share corners with eleven ONd2Bi2 tetrahedra and edges with four ONdBi3 tetrahedra. In the sixth O2- site, O2- is bonded to four Bi+3.29+ atoms to form distorted OBi4 tetrahedra that share corners with seven ONd2Bi2 tetrahedra and edges with three ONdBi3 tetrahedra. In the seventh O2- site, O2- is bonded to three Nd+2.50+ and one Bi+3.29+ atom to form ONd3Bi tetrahedra that share corners with ten ONd2Bi2 tetrahedra, edges with five ONdBi3 tetrahedra, and an edgeedge with one ONdBi3 trigonal pyramid. In the eighth O2- site, O2- is bonded to one Nd+2.50+ and three Bi+3.29+ atoms to form distorted ONdBi3 tetrahedra that share corners with five ONdBi3 tetrahedra, corners with two equivalent ONdBi3 trigonal pyramids, and edges with three ONd3Bi tetrahedra. In the ninth O2- site, O2- is bonded to one Nd+2.50+ and three Bi+3.29+ atoms to form ONdBi3 tetrahedra that share corners with nine ONdBi3 tetrahedra, a cornercorner with one ONdBi3 trigonal pyramid, and edges with six ONd2Bi2 tetrahedra. In the tenth O2- site, O2- is bonded to one Nd+2.50+ and three Bi+3.29+ atoms to form distorted ONdBi3 trigonal pyramids that share corners with six ONdBi3 tetrahedra, corners with two equivalent ONdBi3 trigonal pyramids, and edges with three ONd3Bi tetrahedra. In the eleventh O2- site, O2- is bonded to two equivalent Nd+2.50+ and two Bi+3.29+ atoms to form ONd2Bi2 tetrahedra that share corners with eleven ONd2Bi2 tetrahedra and edges with four ONd3Bi tetrahedra. In the twelfth O2- site, O2- is bonded in a 3-coordinate geometry to three Bi+3.29+ atoms. In the thirteenth O2- site, O2- is bonded in a trigonal planar geometry to three Bi+3.29+ atoms. In the fourteenth O2- site, O2- is bonded to three Nd+2.50+ and one Bi+3.29+ atom to form ONd3Bi tetrahedra that share corners with ten ONd2Bi2 tetrahedra, corners with two equivalent ONdBi3 trigonal pyramids, and edges with five ONd3Bi tetrahedra.