DOE OSTI2020
Ni5P4 crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. there are four inequivalent Ni2+ sites. In the first Ni2+ site, Ni2+ is bonded to five P+2.50- atoms to form distorted NiP5 trigonal bipyramids that share corners with two equivalent PNiP3 tetrahedra, corners with five equivalent NiP4 tetrahedra, corners with eight NiP5 trigonal bipyramids, corners with two equivalent NiP4 trigonal pyramids, edges with two equivalent NiP4 tetrahedra, edges with three NiP5 trigonal bipyramids, and a faceface with one NiP5 trigonal bipyramid. There are a spread of Ni–P bond distances ranging from 2.29–2.46 Å. In the second Ni2+ site, Ni2+ is bonded to four P+2.50- atoms to form NiP4 trigonal pyramids that share corners with twelve NiP5 trigonal bipyramids and edges with three equivalent NiP4 tetrahedra. There are three shorter (2.16 Å) and one longer (2.19 Å) Ni–P bond lengths. In the third Ni2+ site, Ni2+ is bonded to four P+2.50- atoms to form distorted NiP4 tetrahedra that share a cornercorner with one PNiP3 tetrahedra, corners with four equivalent NiP4 tetrahedra, corners with ten NiP5 trigonal bipyramids, edges with four NiP5 trigonal bipyramids, and an edgeedge with one NiP4 trigonal pyramid. There are a spread of Ni–P bond distances ranging from 2.27–2.46 Å. In the fourth Ni2+ site, Ni2+ is bonded to five P+2.50- atoms to form distorted NiP5 trigonal bipyramids that share corners with two equivalent PNiP3 tetrahedra, corners with five equivalent NiP4 tetrahedra, corners with eight NiP5 trigonal bipyramids, corners with two equivalent NiP4 trigonal pyramids, edges with two equivalent NiP4 tetrahedra, edges with three NiP5 trigonal bipyramids, and a faceface with one NiP5 trigonal bipyramid. There are a spread of Ni–P bond distances ranging from 2.28–2.41 Å. There are four inequivalent P+2.50- sites. In the first P+2.50- site, P+2.50- is bonded in a q6 geometry to nine Ni2+ atoms. In the second P+2.50- site, P+2.50- is bonded to one Ni2+ and three equivalent P+2.50- atoms to form PNiP3 tetrahedra that share corners with three equivalent NiP4 tetrahedra and corners with twelve NiP5 trigonal bipyramids. All P–P bond lengths are 2.20 Å. In the third P+2.50- site, P+2.50- is bonded in a 6-coordinate geometry to five Ni2+ and one P+2.50- atom. In the fourth P+2.50- site, P+2.50- is bonded in a 7-coordinate geometry to seven Ni2+ atoms.