UFe7Al3Si2 is beta Uranium-derived structured and crystallizes in the monoclinic Cm space group. U(1) is bonded in a 20-coordinate geometry to one Fe(1), two equivalent Fe(2), two equivalent Fe(3), two equivalent Fe(4), two equivalent Fe(5), four equivalent Fe(6), one Al(1), one Al(2), one Al(3), and four equivalent Si(1) atoms. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 14-coordinate geometry to one U(1), one Fe(4), one Fe(5), two equivalent Fe(3), two equivalent Fe(6), one Al(1), two equivalent Al(2), two equivalent Al(3), and two equivalent Si(1) atoms. In the second Fe site, Fe(2) is bonded to two equivalent U(1), one Fe(4), one Fe(5), two equivalent Fe(6), one Al(2), one Al(3), two equivalent Al(1), and two equivalent Si(1) atoms to form distorted FeU2Al4Fe4Si2 cuboctahedra that share corners with four equivalent Si(1)U2Al3Fe5Si2 cuboctahedra, edges with two equivalent Fe(2)U2Al4Fe4Si2 cuboctahedra, edges with two equivalent Si(1)U2Al3Fe5Si2 cuboctahedra, and faces with four equivalent Si(1)U2Al3Fe5Si2 cuboctahedra. In the third Fe site, Fe(3) is bonded in a 12-coordinate geometry to two equivalent U(1), one Fe(4), one Fe(5), two equivalent Fe(1), two equivalent Fe(6), one Al(2), one Al(3), and two equivalent Si(1) atoms. In the fourth Fe site, Fe(4) is bonded in a 12-coordinate geometry to two equivalent U(1), one Fe(1), one Fe(2), one Fe(3), two equivalent Fe(6), one Al(1), two equivalent Al(3), and two equivalent Si(1) atoms. In the fifth Fe site, Fe(5) is bonded in a 12-coordinate geometry to two equivalent U(1), one Fe(1), one Fe(2), one Fe(3), two equivalent Fe(6), one Al(1), two equivalent Al(2), and two equivalent Si(1) atoms. In the sixth Fe site, Fe(6) is bonded in a 12-coordinate geometry to two equivalent U(1), one Fe(1), one Fe(2), one Fe(3), one Fe(4), one Fe(5), two equivalent Fe(6), one Al(1), one Al(2), and one Al(3) atom. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded in a 14-coordinate geometry to one U(1), one Fe(1), one Fe(4), one Fe(5), two equivalent Fe(2), two equivalent Fe(6), two equivalent Al(2), two equivalent Al(3), and two equivalent Si(1) atoms. In the second Al site, Al(2) is bonded in a 14-coordinate geometry to one U(1), one Fe(2), one Fe(3), two equivalent Fe(1), two equivalent Fe(5), two equivalent Fe(6), one Al(3), two equivalent Al(1), and two equivalent Si(1) atoms. In the third Al site, Al(3) is bonded in a 14-coordinate geometry to one U(1), one Fe(2), one Fe(3), two equivalent Fe(1), two equivalent Fe(4), two equivalent Fe(6), one Al(2), two equivalent Al(1), and two equivalent Si(1) atoms. Si(1) is bonded to two equivalent U(1), one Fe(1), one Fe(2), one Fe(3), one Fe(4), one Fe(5), one Al(1), one Al(2), one Al(3), and two equivalent Si(1) atoms to form distorted SiU2Al3Fe5Si2 cuboctahedra that share corners with two equivalent Fe(2)U2Al4Fe4Si2 cuboctahedra, corners with six equivalent Si(1)U2Al3Fe5Si2 cuboctahedra,  an edgeedge with one Fe(2)U2Al4Fe4Si2 cuboctahedra, faces with two equivalent Fe(2)U2Al4Fe4Si2 cuboctahedra, and faces with two equivalent Si(1)U2Al3Fe5Si2 cuboctahedra.
UFe7Al3Si2 is beta Uranium-derived structured and crystallizes in the monoclinic Cm space group. U(1) is bonded in a 20-coordinate geometry to one Fe(1), two equivalent Fe(2), two equivalent Fe(3), two equivalent Fe(4), two equivalent Fe(5), four equivalent Fe(6), one Al(1), one Al(2), one Al(3), and four equivalent Si(1) atoms. The U(1)-Fe(1) bond length is 2.71 Å. Both U(1)-Fe(2) bond lengths are 3.05 Å. Both U(1)-Fe(3) bond lengths are 2.95 Å. Both U(1)-Fe(4) bond lengths are 3.01 Å. Both U(1)-Fe(5) bond lengths are 3.01 Å. There are two shorter (3.14 Å) and two longer (3.28 Å) U(1)-Fe(6) bond lengths. The U(1)-Al(1) bond length is 3.07 Å. The U(1)-Al(2) bond length is 2.97 Å. The U(1)-Al(3) bond length is 2.98 Å. There are two shorter (3.10 Å) and two longer (3.22 Å) U(1)-Si(1) bond lengths. There are six inequivalent Fe sites. In the first Fe site, Fe(1) is bonded in a 14-coordinate geometry to one U(1), one Fe(4), one Fe(5), two equivalent Fe(3), two equivalent Fe(6), one Al(1), two equivalent Al(2), two equivalent Al(3), and two equivalent Si(1) atoms. The Fe(1)-Fe(4) bond length is 2.70 Å. The Fe(1)-Fe(5) bond length is 2.77 Å. Both Fe(1)-Fe(3) bond lengths are 2.54 Å. Both Fe(1)-Fe(6) bond lengths are 2.46 Å. The Fe(1)-Al(1) bond length is 2.52 Å. Both Fe(1)-Al(2) bond lengths are 2.97 Å. Both Fe(1)-Al(3) bond lengths are 3.03 Å. Both Fe(1)-Si(1) bond lengths are 2.49 Å. In the second Fe site, Fe(2) is bonded to two equivalent U(1), one Fe(4), one Fe(5), two equivalent Fe(6), one Al(2), one Al(3), two equivalent Al(1), and two equivalent Si(1) atoms to form distorted FeU2Al4Fe4Si2 cuboctahedra that share corners with four equivalent Si(1)U2Al3Fe5Si2 cuboctahedra, edges with two equivalent Fe(2)U2Al4Fe4Si2 cuboctahedra, edges with two equivalent Si(1)U2Al3Fe5Si2 cuboctahedra, and faces with four equivalent Si(1)U2Al3Fe5Si2 cuboctahedra. The Fe(2)-Fe(4) bond length is 2.60 Å. The Fe(2)-Fe(5) bond length is 2.71 Å. Both Fe(2)-Fe(6) bond lengths are 2.49 Å. The Fe(2)-Al(2) bond length is 2.63 Å. The Fe(2)-Al(3) bond length is 2.59 Å. Both Fe(2)-Al(1) bond lengths are 2.62 Å. Both Fe(2)-Si(1) bond lengths are 2.39 Å. In the third Fe site, Fe(3) is bonded in a 12-coordinate geometry to two equivalent U(1), one Fe(4), one Fe(5), two equivalent Fe(1), two equivalent Fe(6), one Al(2), one Al(3), and two equivalent Si(1) atoms. The Fe(3)-Fe(4) bond length is 2.61 Å. The Fe(3)-Fe(5) bond length is 2.60 Å. Both Fe(3)-Fe(6) bond lengths are 2.42 Å. The Fe(3)-Al(2) bond length is 2.58 Å. The Fe(3)-Al(3) bond length is 2.67 Å. Both Fe(3)-Si(1) bond lengths are 2.40 Å. In the fourth Fe site, Fe(4) is bonded in a 12-coordinate geometry to two equivalent U(1), one Fe(1), one Fe(2), one Fe(3), two equivalent Fe(6), one Al(1), two equivalent Al(3), and two equivalent Si(1) atoms. Both Fe(4)-Fe(6) bond lengths are 2.44 Å. The Fe(4)-Al(1) bond length is 2.57 Å. Both Fe(4)-Al(3) bond lengths are 2.61 Å. Both Fe(4)-Si(1) bond lengths are 2.36 Å. In the fifth Fe site, Fe(5) is bonded in a 12-coordinate geometry to two equivalent U(1), one Fe(1), one Fe(2), one Fe(3), two equivalent Fe(6), one Al(1), two equivalent Al(2), and two equivalent Si(1) atoms. Both Fe(5)-Fe(6) bond lengths are 2.44 Å. The Fe(5)-Al(1) bond length is 2.64 Å. Both Fe(5)-Al(2) bond lengths are 2.61 Å. Both Fe(5)-Si(1) bond lengths are 2.36 Å. In the sixth Fe site, Fe(6) is bonded in a 12-coordinate geometry to two equivalent U(1), one Fe(1), one Fe(2), one Fe(3), one Fe(4), one Fe(5), two equivalent Fe(6), one Al(1), one Al(2), and one Al(3) atom. There is one shorter (2.29 Å) and one longer (2.43 Å) Fe(6)-Fe(6) bond length. The Fe(6)-Al(1) bond length is 2.55 Å. The Fe(6)-Al(2) bond length is 2.47 Å. The Fe(6)-Al(3) bond length is 2.46 Å. There are three inequivalent Al sites. In the first Al site, Al(1) is bonded in a 14-coordinate geometry to one U(1), one Fe(1), one Fe(4), one Fe(5), two equivalent Fe(2), two equivalent Fe(6), two equivalent Al(2), two equivalent Al(3), and two equivalent Si(1) atoms. Both Al(1)-Al(2) bond lengths are 2.96 Å. Both Al(1)-Al(3) bond lengths are 2.85 Å. Both Al(1)-Si(1) bond lengths are 2.70 Å. In the second Al site, Al(2) is bonded in a 14-coordinate geometry to one U(1), one Fe(2), one Fe(3), two equivalent Fe(1), two equivalent Fe(5), two equivalent Fe(6), one Al(3), two equivalent Al(1), and two equivalent Si(1) atoms. The Al(2)-Al(3) bond length is 2.49 Å. Both Al(2)-Si(1) bond lengths are 2.64 Å. In the third Al site, Al(3) is bonded in a 14-coordinate geometry to one U(1), one Fe(2), one Fe(3), two equivalent Fe(1), two equivalent Fe(4), two equivalent Fe(6), one Al(2), two equivalent Al(1), and two equivalent Si(1) atoms. Both Al(3)-Si(1) bond lengths are 2.59 Å. Si(1) is bonded to two equivalent U(1), one Fe(1), one Fe(2), one Fe(3), one Fe(4), one Fe(5), one Al(1), one Al(2), one Al(3), and two equivalent Si(1) atoms to form distorted SiU2Al3Fe5Si2 cuboctahedra that share corners with two equivalent Fe(2)U2Al4Fe4Si2 cuboctahedra, corners with six equivalent Si(1)U2Al3Fe5Si2 cuboctahedra,  an edgeedge with one Fe(2)U2Al4Fe4Si2 cuboctahedra, faces with two equivalent Fe(2)U2Al4Fe4Si2 cuboctahedra, and faces with two equivalent Si(1)U2Al3Fe5Si2 cuboctahedra. There is one shorter (2.34 Å) and one longer (2.38 Å) Si(1)-Si(1) bond length.