DOE OSTI2020
SmCo3P2 crystallizes in the orthorhombic Pmmn space group. The structure is three-dimensional. there are two inequivalent Sm3+ sites. In the first Sm3+ site, Sm3+ is bonded to six P3- atoms to form distorted SmP6 pentagonal pyramids that share corners with four equivalent SmP6 pentagonal pyramids, corners with twelve CoP4 tetrahedra, edges with two equivalent SmP6 pentagonal pyramids, edges with eight CoP4 tetrahedra, and faces with two equivalent SmP6 pentagonal pyramids. There are two shorter (2.90 Å) and four longer (2.99 Å) Sm–P bond lengths. In the second Sm3+ site, Sm3+ is bonded to six P3- atoms to form distorted SmP6 pentagonal pyramids that share corners with four SmP6 pentagonal pyramids, corners with twelve CoP4 tetrahedra, edges with two SmP6 pentagonal pyramids, edges with seven CoP4 tetrahedra, and faces with two equivalent SmP6 pentagonal pyramids. There are a spread of Sm–P bond distances ranging from 2.85–2.92 Å. There are six inequivalent Co1+ sites. In the first Co1+ site, Co1+ is bonded in a 5-coordinate geometry to five P3- atoms. There are one shorter (2.27 Å) and four longer (2.55 Å) Co–P bond lengths. In the second Co1+ site, Co1+ is bonded in a trigonal planar geometry to three P3- atoms. There are one shorter (2.23 Å) and two longer (2.31 Å) Co–P bond lengths. In the third Co1+ site, Co1+ is bonded to four P3- atoms to form CoP4 tetrahedra that share corners with eight equivalent SmP6 pentagonal pyramids, corners with six CoP4 tetrahedra, edges with two equivalent SmP6 pentagonal pyramids, and edges with four equivalent CoP4 tetrahedra. There are two shorter (2.17 Å) and two longer (2.25 Å) Co–P bond lengths. In the fourth Co1+ site, Co1+ is bonded to four P3- atoms to form CoP4 tetrahedra that share corners with four equivalent SmP6 pentagonal pyramids, corners with seven CoP4 tetrahedra, edges with three equivalent SmP6 pentagonal pyramids, and edges with four CoP4 tetrahedra. There are a spread of Co–P bond distances ranging from 2.23–2.32 Å. In the fifth Co1+ site, Co1+ is bonded to four P3- atoms to form CoP4 tetrahedra that share corners with six SmP6 pentagonal pyramids, corners with six CoP4 tetrahedra, edges with four SmP6 pentagonal pyramids, and edges with four CoP4 tetrahedra. There are a spread of Co–P bond distances ranging from 2.25–2.42 Å. In the sixth Co1+ site, Co1+ is bonded to four P3- atoms to form CoP4 tetrahedra that share corners with four equivalent SmP6 pentagonal pyramids, corners with eleven CoP4 tetrahedra, edges with three SmP6 pentagonal pyramids, and edges with three CoP4 tetrahedra. There are two shorter (2.31 Å) and two longer (2.35 Å) Co–P bond lengths. There are four inequivalent P3- sites. In the first P3- site, P3- is bonded in a 9-coordinate geometry to two equivalent Sm3+ and seven Co1+ atoms. In the second P3- site, P3- is bonded in a 9-coordinate geometry to four equivalent Sm3+ and five Co1+ atoms. In the third P3- site, P3- is bonded in a 9-coordinate geometry to two equivalent Sm3+ and seven Co1+ atoms. In the fourth P3- site, P3- is bonded in a 9-coordinate geometry to four Sm3+ and five Co1+ atoms.