U3Si crystallizes in the tetragonal I4/mcm space group. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 12-coordinate geometry to eight equivalent U(2) and four equivalent Si(1) atoms. In the second U site, U(2) is bonded in a 12-coordinate geometry to four equivalent U(1), four equivalent U(2), and four equivalent Si(1) atoms. Si(1) is bonded to four equivalent U(1) and eight equivalent U(2) atoms to form a mixture of corner and face-sharing SiU12 cuboctahedra.
U3Si crystallizes in the tetragonal I4/mcm space group. There are two inequivalent U sites. In the first U site, U(1) is bonded in a 12-coordinate geometry to eight equivalent U(2) and four equivalent Si(1) atoms. There are four shorter (2.84 Å) and four longer (3.18 Å) U(1)-U(2) bond lengths. All U(1)-Si(1) bond lengths are 2.99 Å. In the second U site, U(2) is bonded in a 12-coordinate geometry to four equivalent U(1), four equivalent U(2), and four equivalent Si(1) atoms. All U(2)-U(2) bond lengths are 3.01 Å. All U(2)-Si(1) bond lengths are 3.01 Å. Si(1) is bonded to four equivalent U(1) and eight equivalent U(2) atoms to form a mixture of corner and face-sharing SiU12 cuboctahedra.