DOE OSTI2020
Nd2Co12P7 crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are two inequivalent Nd3+ sites. In the first Nd3+ site, Nd3+ is bonded to six P3- atoms to form distorted NdP6 pentagonal pyramids that share corners with twelve CoP4 tetrahedra, edges with twelve CoP4 tetrahedra, and faces with two equivalent NdP6 pentagonal pyramids. There are four shorter (2.91 Å) and two longer (2.92 Å) Nd–P bond lengths. In the second Nd3+ site, Nd3+ is bonded to six P3- atoms to form distorted NdP6 pentagonal pyramids that share corners with twelve CoP4 tetrahedra, edges with nine CoP4 tetrahedra, and faces with two equivalent NdP6 pentagonal pyramids. All Nd–P bond lengths are 2.89 Å. There are eleven inequivalent Co+1.25+ sites. In the first Co+1.25+ site, Co+1.25+ is bonded to four P3- atoms to form CoP4 tetrahedra that share corners with two equivalent NdP6 pentagonal pyramids, corners with twelve CoP4 tetrahedra, edges with three NdP6 pentagonal pyramids, and edges with three CoP4 tetrahedra. There are three shorter (2.29 Å) and one longer (2.30 Å) Co–P bond lengths. In the second Co+1.25+ site, Co+1.25+ is bonded to four P3- atoms to form CoP4 tetrahedra that share corners with two equivalent NdP6 pentagonal pyramids, corners with twelve CoP4 tetrahedra, edges with three NdP6 pentagonal pyramids, and edges with three CoP4 tetrahedra. There are three shorter (2.29 Å) and one longer (2.30 Å) Co–P bond lengths. In the third Co+1.25+ site, Co+1.25+ is bonded to four P3- atoms to form CoP4 tetrahedra that share corners with two equivalent NdP6 pentagonal pyramids, corners with twelve CoP4 tetrahedra, edges with three NdP6 pentagonal pyramids, and edges with three CoP4 tetrahedra. All Co–P bond lengths are 2.29 Å. In the fourth Co+1.25+ site, Co+1.25+ is bonded to four P3- atoms to form CoP4 tetrahedra that share corners with two equivalent NdP6 pentagonal pyramids, corners with ten CoP4 tetrahedra, edges with three NdP6 pentagonal pyramids, and edges with four CoP4 tetrahedra. There are a spread of Co–P bond distances ranging from 2.26–2.36 Å. In the fifth Co+1.25+ site, Co+1.25+ is bonded to four P3- atoms to form CoP4 tetrahedra that share corners with two equivalent NdP6 pentagonal pyramids, corners with ten CoP4 tetrahedra, edges with three NdP6 pentagonal pyramids, and edges with four CoP4 tetrahedra. There are a spread of Co–P bond distances ranging from 2.26–2.36 Å. In the sixth Co+1.25+ site, Co+1.25+ is bonded to four P3- atoms to form CoP4 tetrahedra that share corners with two equivalent NdP6 pentagonal pyramids, corners with ten CoP4 tetrahedra, edges with three NdP6 pentagonal pyramids, and edges with four CoP4 tetrahedra. There are a spread of Co–P bond distances ranging from 2.26–2.36 Å. In the seventh Co+1.25+ site, Co+1.25+ is bonded to four P3- atoms to form CoP4 tetrahedra that share corners with four NdP6 pentagonal pyramids, corners with ten CoP4 tetrahedra, an edgeedge with one NdP6 pentagonal pyramid, and edges with three CoP4 tetrahedra. There are a spread of Co–P bond distances ranging from 2.13–2.30 Å. In the eighth Co+1.25+ site, Co+1.25+ is bonded to four P3- atoms to form CoP4 tetrahedra that share corners with four NdP6 pentagonal pyramids, corners with ten CoP4 tetrahedra, an edgeedge with one NdP6 pentagonal pyramid, and edges with three CoP4 tetrahedra. There are a spread of Co–P bond distances ranging from 2.13–2.30 Å. In the ninth Co+1.25+ site, Co+1.25+ is bonded to four P3- atoms to form CoP4 tetrahedra that share corners with four NdP6 pentagonal pyramids, corners with ten CoP4 tetrahedra, an edgeedge with one NdP6 pentagonal pyramid, and edges with three CoP4 tetrahedra. There are a spread of Co–P bond distances ranging from 2.13–2.30 Å. In the tenth Co+1.25+ site, Co+1.25+ is bonded in a 5-coordinate geometry to five P3- atoms. There are a spread of Co–P bond distances ranging from 2.22–2.57 Å. In the eleventh Co+1.25+ site, Co+1.25+ is bonded in a 5-coordinate geometry to five P3- atoms. There are a spread of Co–P bond distances ranging from 2.22–2.57 Å. There are six inequivalent P3- sites. In the first P3- site, P3- is bonded in a 9-coordinate geometry to two equivalent Nd3+ and seven Co+1.25+ atoms. In the second P3- site, P3- is bonded in a 9-coordinate geometry to two equivalent Nd3+ and seven Co+1.25+ atoms. The P–Co bond length is 2.22 Å. In the third P3- site, P3- is bonded in a 9-coordinate geometry to two equivalent Nd3+ and seven Co+1.25+ atoms. In the fourth P3- site, P3- is bonded in a 3-coordinate geometry to nine Co+1.25+ atoms. In the fifth P3- site, P3- is bonded in a 9-coordinate geometry to two equivalent Nd3+ and seven Co+1.25+ atoms. In the sixth P3- site, P3- is bonded in a 9-coordinate geometry to two equivalent Nd3+ and seven Co+1.25+ atoms.