DOE OSTI2020
NbNi3P2 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are three inequivalent Nb2+ sites. In the first Nb2+ site, Nb2+ is bonded to five P3- atoms to form distorted NbP5 trigonal bipyramids that share a cornercorner with one NbP5 square pyramid, corners with three equivalent NiP5 square pyramids, corners with six NiP4 tetrahedra, corners with two equivalent NiP5 trigonal bipyramids, corners with four equivalent NbP5 trigonal bipyramids, an edgeedge with one NiP5 square pyramid, edges with six NiP4 tetrahedra, an edgeedge with one NiP5 trigonal bipyramid, and edges with four NbP5 trigonal bipyramids. There are a spread of Nb–P bond distances ranging from 2.51–2.58 Å. In the second Nb2+ site, Nb2+ is bonded to five P3- atoms to form distorted NbP5 square pyramids that share corners with three equivalent NiP5 square pyramids, corners with six NiP4 tetrahedra, a cornercorner with one NbP5 trigonal bipyramid, corners with six NiP5 trigonal bipyramids, an edgeedge with one NiP5 square pyramid, edges with two equivalent NbP5 square pyramids, edges with six NiP4 tetrahedra, and edges with three NiP5 trigonal bipyramids. There are a spread of Nb–P bond distances ranging from 2.50–2.57 Å. In the third Nb2+ site, Nb2+ is bonded to five P3- atoms to form distorted NbP5 trigonal bipyramids that share corners with two equivalent NiP5 square pyramids, corners with six NiP4 tetrahedra, corners with four equivalent NbP5 trigonal bipyramids, corners with four NiP5 trigonal bipyramids, an edgeedge with one NiP5 square pyramid, edges with six NiP4 tetrahedra, an edgeedge with one NiP5 trigonal bipyramid, and edges with four NbP5 trigonal bipyramids. There are a spread of Nb–P bond distances ranging from 2.51–2.58 Å. There are nine inequivalent Ni+1.33+ sites. In the first Ni+1.33+ site, Ni+1.33+ is bonded to four P3- atoms to form NiP4 tetrahedra that share corners with two equivalent NbP5 square pyramids, corners with ten NiP4 tetrahedra, corners with two equivalent NbP5 trigonal bipyramids, corners with two equivalent NiP5 trigonal bipyramids, edges with two NiP4 tetrahedra, edges with two equivalent NbP5 trigonal bipyramids, and edges with four NiP5 trigonal bipyramids. There are a spread of Ni–P bond distances ranging from 2.16–2.37 Å. In the second Ni+1.33+ site, Ni+1.33+ is bonded to four P3- atoms to form NiP4 tetrahedra that share corners with two equivalent NiP5 square pyramids, corners with ten NiP4 tetrahedra, corners with two equivalent NbP5 trigonal bipyramids, corners with two equivalent NiP5 trigonal bipyramids, edges with two equivalent NbP5 square pyramids, edges with two equivalent NiP5 square pyramids, edges with two NiP4 tetrahedra, and edges with two equivalent NbP5 trigonal bipyramids. There are a spread of Ni–P bond distances ranging from 2.24–2.40 Å. In the third Ni+1.33+ site, Ni+1.33+ is bonded to four P3- atoms to form NiP4 tetrahedra that share corners with two equivalent NbP5 square pyramids, corners with ten NiP4 tetrahedra, corners with two equivalent NbP5 trigonal bipyramids, corners with two equivalent NiP5 trigonal bipyramids, edges with two equivalent NbP5 square pyramids, edges with two equivalent NiP5 square pyramids, edges with two NiP4 tetrahedra, and edges with two equivalent NiP5 trigonal bipyramids. There are a spread of Ni–P bond distances ranging from 2.15–2.34 Å. In the fourth Ni+1.33+ site, Ni+1.33+ is bonded to four P3- atoms to form NiP4 tetrahedra that share corners with two equivalent NiP5 square pyramids, corners with ten NiP4 tetrahedra, corners with two equivalent NbP5 trigonal bipyramids, corners with two equivalent NiP5 trigonal bipyramids, edges with two NiP4 tetrahedra, edges with two equivalent NiP5 trigonal bipyramids, and edges with four NbP5 trigonal bipyramids. There are a spread of Ni–P bond distances ranging from 2.22–2.43 Å. In the fifth Ni+1.33+ site, Ni+1.33+ is bonded to four P3- atoms to form NiP4 tetrahedra that share corners with two equivalent NiP5 square pyramids, corners with ten NiP4 tetrahedra, corners with two equivalent NbP5 trigonal bipyramids, corners with two equivalent NiP5 trigonal bipyramids, edges with two equivalent NbP5 square pyramids, edges with two NiP4 tetrahedra, and edges with four NiP5 trigonal bipyramids. There are three shorter (2.29 Å) and one longer (2.32 Å) Ni–P bond lengths. In the sixth Ni+1.33+ site, Ni+1.33+ is bonded to four P3- atoms to form NiP4 tetrahedra that share corners with two equivalent NbP5 square pyramids, corners with ten NiP4 tetrahedra, corners with two equivalent NbP5 trigonal bipyramids, corners with two equivalent NiP5 trigonal bipyramids, edges with two equivalent NiP5 square pyramids, edges with two NiP4 tetrahedra, and edges with four NbP5 trigonal bipyramids. There are a spread of Ni–P bond distances ranging from 2.21–2.47 Å. In the seventh Ni+1.33+ site, Ni+1.33+ is bonded to five P3- atoms to form distorted NiP5 trigonal bipyramids that share corners with two equivalent NbP5 square pyramids, corners with six NiP4 tetrahedra, corners with three equivalent NiP5 trigonal bipyramids, corners with five NbP5 trigonal bipyramids, an edgeedge with one NbP5 square pyramid, edges with six NiP4 tetrahedra, edges with two NbP5 trigonal bipyramids, and edges with three NiP5 trigonal bipyramids. There are a spread of Ni–P bond distances ranging from 2.34–2.53 Å. In the eighth Ni+1.33+ site, Ni+1.33+ is bonded to five P3- atoms to form distorted NiP5 square pyramids that share corners with three equivalent NbP5 square pyramids, corners with six NiP4 tetrahedra, corners with two equivalent NiP5 trigonal bipyramids, corners with five NbP5 trigonal bipyramids, an edgeedge with one NbP5 square pyramid, edges with two equivalent NiP5 square pyramids, edges with six NiP4 tetrahedra, an edgeedge with one NiP5 trigonal bipyramid, and edges with two NbP5 trigonal bipyramids. There are a spread of Ni–P bond distances ranging from 2.32–2.55 Å. In the ninth Ni+1.33+ site, Ni+1.33+ is bonded to five P3- atoms to form distorted NiP5 trigonal bipyramids that share corners with two equivalent NiP5 square pyramids, corners with four equivalent NbP5 square pyramids, corners with six NiP4 tetrahedra, a cornercorner with one NbP5 trigonal bipyramid, corners with three equivalent NiP5 trigonal bipyramids, an edgeedge with one NiP5 square pyramid, edges with two equivalent NbP5 square pyramids, edges with six NiP4 tetrahedra, and edges with three NiP5 trigonal bipyramids. There are a spread of Ni–P bond distances ranging from 2.35–2.54 Å. There are six inequivalent P3- sites. In the first P3- site, P3- is bonded in a 9-coordinate geometry to two equivalent Nb2+ and seven Ni+1.33+ atoms. In the second P3- site, P3- is bonded in a 9-coordinate geometry to four Nb2+ and five Ni+1.33+ atoms. In the third P3- site, P3- is bonded in a 9-coordinate geometry to two equivalent Nb2+ and seven Ni+1.33+ atoms. In the fourth P3- site, P3- is bonded in a 9-coordinate geometry to four Nb2+ and five Ni+1.33+ atoms. In the fifth P3- site, P3- is bonded in a 9-coordinate geometry to one Nb2+ and eight Ni+1.33+ atoms. In the sixth P3- site, P3- is bonded in a 9-coordinate geometry to two Nb2+ and seven Ni+1.33+ atoms.