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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on U(SiNi)2 by Materials Project

UNi2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U4+ is bonded in a distorted body-centered cubic geometry to eight equivalent Si4- atoms. All U–Si bond lengths are 3.02 Å. Ni2+ is bonded to four equivalent Si4- atoms to form a mixture of edge and corner-sharing NiSi4 tetrahedra. All Ni–Si bond lengths are 2.31 Å. Si4- is bonded in a 9-coordinate geometry to four equivalent U4+, four equivalent Ni2+, and one Si4- atom. The Si–Si bond length is 2.33 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on USiNi by Materials Project

UNiSi crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. U3+ is bonded to two equivalent U3+ and five equivalent Si4- atoms to form distorted UU2Si5 pentagonal bipyramids that share corners with eight equivalent UU2Si5 pentagonal bipyramids, corners with eight equivalent NiSi4 tetrahedra, edges with four equivalent UU2Si5 pentagonal bipyramids, edges with six equivalent NiSi4 tetrahedra, and faces with two equivalent UU2Si5 pentagonal bipyramids. Both U–U bond lengths are 2.61 Å. There are one shorter (2.85 Å) and four longer (2.89 Å) U–Si bond lengths. Ni1+ is bonded to four equivalent Si4- atoms to form NiSi4 tetrahedra that share corners with eight equivalent UU2Si5 pentagonal bipyramids, corners with eight equivalent NiSi4 tetrahedra, edges with six equivalent UU2Si5 pentagonal bipyramids, and edges with two equivalent NiSi4 tetrahedra. There are a spread of Ni–Si bond distances ranging from 2.35–2.49 Å. Si4- is bonded in a 9-coordinate geometry to five equivalent U3+ and four equivalent Ni1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U2Si3Ni by Materials Project

U2NiSi3 crystallizes in the orthorhombic Pmm2 space group. The structure is three-dimensional. there are two inequivalent U5+ sites. In the first U5+ site, U5+ is bonded in a distorted q4 geometry to ten Si4- atoms. There are four shorter (3.00 Å) and six longer (3.03 Å) U–Si bond lengths. In the second U5+ site, U5+ is bonded to eight Si4- atoms to form a mixture of distorted corner, edge, and face-sharing USi8 hexagonal bipyramids. There are a spread of U–Si bond distances ranging from 2.95–2.99 Å. Ni2+ is bonded in a trigonal planar geometry to three Si4- atoms. There are one shorter (2.24 Å) and two longer (2.27 Å) Ni–Si bond lengths. There are three inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to six U5+ and three Si4- atoms. There are one shorter (2.33 Å) and two longer (2.34 Å) Si–Si bond lengths. In the second Si4- site, Si4- is bonded in a 9-coordinate geometry to six U5+, two equivalent Ni2+, and one Si4- atom. In the third Si4- site, Si4- is bonded in a 9-coordinate geometry to six U5+, one Ni2+, and two equivalent Si4- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on USi3Ni2 by Materials Project

UNi2Si3 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U6+ is bonded in a 8-coordinate geometry to eight Si4- atoms. There are four shorter (2.96 Å) and four longer (3.06 Å) U–Si bond lengths. There are two inequivalent Ni3+ sites. In the first Ni3+ site, Ni3+ is bonded to four equivalent Si4- atoms to form a mixture of corner and edge-sharing NiSi4 tetrahedra. All Ni–Si bond lengths are 2.32 Å. In the second Ni3+ site, Ni3+ is bonded in a 5-coordinate geometry to five Si4- atoms. There are four shorter (2.27 Å) and one longer (2.29 Å) Ni–Si bond lengths. There are two inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 3-coordinate geometry to two equivalent U6+, two equivalent Ni3+, and five equivalent Si4- atoms. There are one shorter (2.34 Å) and four longer (2.75 Å) Si–Si bond lengths. In the second Si4- site, Si4- is bonded in a 9-coordinate geometry to four equivalent U6+ and five Ni3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(SiNi5)2 by Materials Project

UNi10Si2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to sixteen Ni and four equivalent Si atoms. There are a spread of U–Ni bond distances ranging from 2.67–3.09 Å. All U–Si bond lengths are 3.16 Å. There are four inequivalent Ni sites. In the first Ni site, Ni is bonded in a 8-coordinate geometry to one U, eleven Ni, and two equivalent Si atoms. There are a spread of Ni–Ni bond distances ranging from 2.42–2.96 Å. Both Ni–Si bond lengths are 2.54 Å. In the second Ni site, Ni is bonded in a 1-coordinate geometry to one U, eleven Ni, and two equivalent Si atoms. There are a spread of Ni–Ni bond distances ranging from 2.48–2.71 Å. Both Ni–Si bond lengths are 2.40 Å. In the third Ni site, Ni is bonded in a 2-coordinate geometry to two equivalent U, nine Ni, and two equivalent Si atoms. There are four shorter (2.44 Å) and one longer (2.83 Å) Ni–Ni bond lengths. Both Ni–Si bond lengths are 2.50 Å. In the fourth Ni site, Ni is bonded to two equivalent U, eight Ni, and two equivalent Si atoms to form distorted NiU2Si2Ni8 cuboctahedra that share corners with four equivalent SiU2Ni10 cuboctahedra, corners with ten equivalent NiU2Si2Ni8 cuboctahedra, edges with two equivalent SiU2Ni10 cuboctahedra, edges with four equivalent NiU2Si2Ni8 cuboctahedra, faces with four equivalent SiU2Ni10 cuboctahedra, and faces with six equivalent NiU2Si2Ni8 cuboctahedra. Both Ni–Ni bond lengths are 2.40 Å. Both Ni–Si bond lengths are 2.30 Å. Si is bonded to two equivalent U and ten Ni atoms to form distorted SiU2Ni10 cuboctahedra that share corners with six equivalent SiU2Ni10 cuboctahedra, corners with eight equivalent NiU2Si2Ni8 cuboctahedra, edges with three equivalent SiU2Ni10 cuboctahedra, edges with four equivalent NiU2Si2Ni8 cuboctahedra, a faceface with one SiU2Ni10 cuboctahedra, and faces with eight equivalent NiU2Si2Ni8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U2(Si2Ni)3 by Materials Project

U2(NiSi2)3 crystallizes in the orthorhombic Cmmm space group. The structure is three-dimensional. U5+ is bonded in a 10-coordinate geometry to ten Si+2.67- atoms. There are a spread of U–Si bond distances ranging from 3.00–3.08 Å. There are two inequivalent Ni2+ sites. In the first Ni2+ site, Ni2+ is bonded in a 5-coordinate geometry to five Si+2.67- atoms. There are one shorter (2.25 Å) and four longer (2.29 Å) Ni–Si bond lengths. In the second Ni2+ site, Ni2+ is bonded in a body-centered cubic geometry to eight Si+2.67- atoms. All Ni–Si bond lengths are 2.36 Å. There are three inequivalent Si+2.67- sites. In the first Si+2.67- site, Si+2.67- is bonded in a 4-coordinate geometry to two equivalent U5+, four Ni2+, and five Si+2.67- atoms. There are one shorter (2.54 Å) and four longer (2.81 Å) Si–Si bond lengths. In the second Si+2.67- site, Si+2.67- is bonded in a 4-coordinate geometry to two equivalent U5+, four Ni2+, and five Si+2.67- atoms. The Si–Si bond length is 2.55 Å. In the third Si+2.67- site, Si+2.67- is bonded in a 9-coordinate geometry to six equivalent U5+, one Ni2+, and two equivalent Si+2.67- atoms. Both Si–Si bond lengths are 2.33 Å.

36 MATERIALS SCIENCE↗