DOE OSTI2020
Nd4O4(GeO4) crystallizes in the orthorhombic Pmc2_1 space group. The structure is three-dimensional. there are six inequivalent Nd3+ sites. In the first Nd3+ site, Nd3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Nd–O bond distances ranging from 2.34–2.89 Å. In the second Nd3+ site, Nd3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Nd–O bond distances ranging from 2.27–2.74 Å. In the third Nd3+ site, Nd3+ is bonded to seven O2- atoms to form distorted NdO7 pentagonal bipyramids that share a cornercorner with one GeO4 tetrahedra and edges with two equivalent NdO7 pentagonal bipyramids. There are a spread of Nd–O bond distances ranging from 2.36–2.59 Å. In the fourth Nd3+ site, Nd3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Nd–O bond distances ranging from 2.33–2.90 Å. In the fifth Nd3+ site, Nd3+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Nd–O bond distances ranging from 2.27–2.76 Å. In the sixth Nd3+ site, Nd3+ is bonded to seven O2- atoms to form distorted NdO7 pentagonal bipyramids that share a cornercorner with one GeO4 tetrahedra and edges with two equivalent NdO7 pentagonal bipyramids. There are a spread of Nd–O bond distances ranging from 2.36–2.59 Å. There are two inequivalent Ge4+ sites. In the first Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one NdO7 pentagonal bipyramid. There are a spread of Ge–O bond distances ranging from 1.78–1.80 Å. In the second Ge4+ site, Ge4+ is bonded to four O2- atoms to form GeO4 tetrahedra that share a cornercorner with one NdO7 pentagonal bipyramid. There are a spread of Ge–O bond distances ranging from 1.78–1.80 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to three Nd3+ and one Ge4+ atom. In the second O2- site, O2- is bonded to four Nd3+ atoms to form distorted ONd4 tetrahedra that share corners with four equivalent ONd4 tetrahedra, corners with two equivalent ONd3Ge trigonal pyramids, and edges with four ONd4 tetrahedra. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three Nd3+ and one Ge4+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Nd3+ and one Ge4+ atom. In the fifth O2- site, O2- is bonded to four Nd3+ atoms to form distorted ONd4 tetrahedra that share corners with four equivalent ONd4 tetrahedra, a cornercorner with one ONd3Ge trigonal pyramid, and edges with four ONd4 tetrahedra. In the sixth O2- site, O2- is bonded to three Nd3+ and one Ge4+ atom to form distorted corner-sharing ONd3Ge trigonal pyramids. In the seventh O2- site, O2- is bonded to four Nd3+ atoms to form ONd4 tetrahedra that share corners with four equivalent ONd4 tetrahedra, corners with two equivalent ONd3Ge trigonal pyramids, and edges with four ONd4 tetrahedra. In the eighth O2- site, O2- is bonded in a 4-coordinate geometry to three Nd3+ and one Ge4+ atom. In the ninth O2- site, O2- is bonded to four Nd3+ atoms to form ONd4 tetrahedra that share corners with eight ONd4 tetrahedra, a cornercorner with one ONd3Ge trigonal pyramid, and edges with four ONd4 tetrahedra. In the tenth O2- site, O2- is bonded to four Nd3+ atoms to form ONd4 tetrahedra that share corners with eight ONd4 tetrahedra, a cornercorner with one ONd3Ge trigonal pyramid, and edges with four ONd4 tetrahedra. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to three Nd3+ and one Ge4+ atom. In the twelfth O2- site, O2- is bonded to four Nd3+ atoms to form ONd4 tetrahedra that share corners with four equivalent ONd4 tetrahedra, a cornercorner with one ONd3Ge trigonal pyramid, and edges with four ONd4 tetrahedra.