U2W3Si4 crystallizes in the monoclinic P2_1/c space group. U(1) is bonded in a 11-coordinate geometry to two equivalent W(1), two equivalent W(2), three equivalent Si(1), and four equivalent Si(2) atoms. There are two inequivalent W sites. In the first W site, W(1) is bonded in a 6-coordinate geometry to two equivalent U(1), three equivalent Si(1), and three equivalent Si(2) atoms. In the second W site, W(2) is bonded to four equivalent U(1), two equivalent Si(2), and four equivalent Si(1) atoms to form distorted edge-sharing WU4Si6 octahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to three equivalent U(1), two equivalent W(2), three equivalent W(1), and one Si(1) atom. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to four equivalent U(1), one W(2), three equivalent W(1), and one Si(2) atom.
U2W3Si4 crystallizes in the monoclinic P2_1/c space group. U(1) is bonded in a 11-coordinate geometry to two equivalent W(1), two equivalent W(2), three equivalent Si(1), and four equivalent Si(2) atoms. There is one shorter (3.18 Å) and one longer (3.24 Å) U(1)-W(1) bond length. There is one shorter (3.24 Å) and one longer (3.26 Å) U(1)-W(2) bond length. There are a spread of U(1)-Si(1) bond distances ranging from 2.82-2.89 Å. There are a spread of U(1)-Si(2) bond distances ranging from 2.81-3.00 Å. There are two inequivalent W sites. In the first W site, W(1) is bonded in a 6-coordinate geometry to two equivalent U(1), three equivalent Si(1), and three equivalent Si(2) atoms. There are two shorter (2.57 Å) and one longer (2.65 Å) W(1)-Si(1) bond length. There are a spread of W(1)-Si(2) bond distances ranging from 2.53-2.60 Å. In the second W site, W(2) is bonded to four equivalent U(1), two equivalent Si(2), and four equivalent Si(1) atoms to form distorted edge-sharing WU4Si6 octahedra. Both W(2)-Si(2) bond lengths are 2.67 Å. There are two shorter (2.64 Å) and two longer (2.69 Å) W(2)-Si(1) bond lengths. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded in a 9-coordinate geometry to three equivalent U(1), two equivalent W(2), three equivalent W(1), and one Si(1) atom. The Si(1)-Si(1) bond length is 2.55 Å. In the second Si site, Si(2) is bonded in a 9-coordinate geometry to four equivalent U(1), one W(2), three equivalent W(1), and one Si(2) atom. The Si(2)-Si(2) bond length is 2.52 Å.