Materials Data on U6Co30Si19 by Materials Project

Abstract

U6Co30Si19 crystallizes in the hexagonal P6_3/m space group. The structure is three-dimensional. there are two inequivalent U3+ sites. In the first U3+ site, U3+ is bonded to six Si4- atoms to form distorted USi6 pentagonal pyramids that share corners with six CoSi4 tetrahedra, edges with nine CoSi4 tetrahedra, and faces with two equivalent USi6 pentagonal pyramids. There are a spread of U–Si bond distances ranging from 2.92–2.94 Å. In the second U3+ site, U3+ is bonded to six Si4- atoms to form distorted USi6 pentagonal pyramids that share corners with four CoSi4 tetrahedra, edges with eight CoSi4 tetrahedra, and faces with two equivalent USi6 pentagonal pyramids. There are two shorter (2.91 Å) and four longer (2.92 Å) U–Si bond lengths. There are ten inequivalent Co+1.93+ sites. In the first Co+1.93+ site, Co+1.93+ is bonded to four Si4- atoms to form CoSi4 tetrahedra that share corners with two equivalent USi6 pentagonal pyramids, corners with ten CoSi4 tetrahedra, edges with three USi6 pentagonal pyramids, and edges with three CoSi4 tetrahedra. There are a spread of Co–Si bond distances ranging from 2.28–2.33 Å. In the second Co+1.93+ site, Co+1.93+ is bonded to four Si4- atoms to form CoSi4 tetrahedra that share corners with two equivalent USi6 pentagonal pyramids, corners with ten CoSi4 tetrahedra, edges with three equivalent USi6 pentagonal pyramids, and edges with two equivalent CoSi4 tetrahedra. There are a spread of Co–Si bond distances ranging from 2.28–2.32 Å. In the third Co+1.93+ site, Co+1.93+ is bonded to four Si4- atoms to form CoSi4 tetrahedra that share corners with two equivalent USi6 pentagonal pyramids, corners with ten CoSi4 tetrahedra, edges with three USi6 pentagonal pyramids, and edges with three CoSi4 tetrahedra. There are a spread of Co–Si bond distances ranging from 2.27–2.33 Å. In the fourth Co+1.93+ site, Co+1.93+ is bonded in a distorted trigonal non-coplanar geometry to three equivalent Si4- atoms. There are one shorter (2.25 Å) and two longer (2.39 Å) Co–Si bond lengths. In the fifth Co+1.93+ site, Co+1.93+ is bonded in a 5-coordinate geometry to five Si4- atoms. There are a spread of Co–Si bond distances ranging from 2.24–2.37 Å. In the sixth Co+1.93+ site, Co+1.93+ is bonded to four Si4- atoms to form CoSi4 tetrahedra that share corners with two equivalent USi6 pentagonal pyramids, corners with eight CoSi4 tetrahedra, edges with three equivalent USi6 pentagonal pyramids, and edges with three CoSi4 tetrahedra. There are two shorter (2.31 Å) and two longer (2.35 Å) Co–Si bond lengths. In the seventh Co+1.93+ site, Co+1.93+ is bonded in a 5-coordinate geometry to five Si4- atoms. There are a spread of Co–Si bond distances ranging from 2.24–2.37 Å. In the eighth Co+1.93+ site, Co+1.93+ is bonded in a 5-coordinate geometry to five Si4- atoms. There are one shorter (2.27 Å) and four longer (2.37 Å) Co–Si bond lengths. In the ninth Co+1.93+ site, Co+1.93+ is bonded to four Si4- atoms to form CoSi4 tetrahedra that share corners with two equivalent USi6 pentagonal pyramids, corners with ten CoSi4 tetrahedra, edges with three equivalent USi6 pentagonal pyramids, and edges with three CoSi4 tetrahedra. There are a spread of Co–Si bond distances ranging from 2.28–2.34 Å. In the tenth Co+1.93+ site, Co+1.93+ is bonded to four Si4- atoms to form CoSi4 tetrahedra that share corners with eight CoSi4 tetrahedra, edges with two equivalent USi6 pentagonal pyramids, and edges with two equivalent CoSi4 tetrahedra. There are two shorter (2.29 Å) and two longer (2.36 Å) Co–Si bond lengths. There are seven inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to two equivalent U3+ and seven Co+1.93+ atoms. In the second Si4- site, Si4- is bonded in a 10-coordinate geometry to two equivalent U3+, six Co+1.93+, and two Si4- atoms. There are one shorter (2.61 Å) and one longer (2.62 Å) Si–Si bond lengths. In the third Si4- site, Si4- is bonded in a 9-coordinate geometry to two equivalent U3+ and seven Co+1.93+ atoms. In the fourth Si4- site, Si4- is bonded in a 9-coordinate geometry to nine Co+1.93+ atoms. In the fifth Si4- site, Si4- is bonded in a 10-coordinate geometry to two equivalent U3+, six Co+1.93+, and two Si4- atoms. The Si–Si bond length is 2.59 Å. In the sixth Si4- site, Si4- is bonded in a 10-coordinate geometry to two equivalent U3+, six Co+1.93+, and two Si4- atoms. In the seventh Si4- site, Si4- is bonded in a 9-coordinate geometry to two equivalent U3+ and seven Co+1.93+ atoms.