UBi4(AsO8)2 crystallizes in the triclinic P-1 space group. U(1) is bonded to two equivalent O(1), two equivalent O(6), and two equivalent O(7) atoms to form UO6 octahedra that share corners with four equivalent As(1)O4 tetrahedra. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 7-coordinate geometry to one O(4), one O(5), one O(8), two equivalent O(2), and two equivalent O(3) atoms. In the second Bi site, Bi(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(5), one O(8), and two equivalent O(3) atoms. As(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form AsO4 tetrahedra that share corners with two equivalent U(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 31-39°. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one U(1) and one Bi(2) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Bi(2) and two equivalent Bi(1) atoms. In the third O site, O(3) is bonded to two equivalent Bi(1) and two equivalent Bi(2) atoms to form edge-sharing OBi4 tetrahedra. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Bi(1) and one As(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Bi(1), one Bi(2), and one As(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one U(1) and one As(1) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one U(1) and one As(1) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Bi(1) and one Bi(2) atom.
UBi4(AsO8)2 crystallizes in the triclinic P-1 space group. U(1) is bonded to two equivalent O(1), two equivalent O(6), and two equivalent O(7) atoms to form UO6 octahedra that share corners with four equivalent As(1)O4 tetrahedra. Both U(1)-O(1) bond lengths are 1.85 Å. Both U(1)-O(6) bond lengths are 2.25 Å. Both U(1)-O(7) bond lengths are 2.29 Å. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 7-coordinate geometry to one O(4), one O(5), one O(8), two equivalent O(2), and two equivalent O(3) atoms. The Bi(1)-O(4) bond length is 2.28 Å. The Bi(1)-O(5) bond length is 2.36 Å. The Bi(1)-O(8) bond length is 2.05 Å. There is one shorter (2.14 Å) and one longer (2.20 Å) Bi(1)-O(2) bond length. There is one shorter (2.18 Å) and one longer (2.50 Å) Bi(1)-O(3) bond length. In the second Bi site, Bi(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(5), one O(8), and two equivalent O(3) atoms. The Bi(2)-O(1) bond length is 2.63 Å. The Bi(2)-O(2) bond length is 2.58 Å. The Bi(2)-O(5) bond length is 2.44 Å. The Bi(2)-O(8) bond length is 2.22 Å. There is one shorter (2.33 Å) and one longer (2.38 Å) Bi(2)-O(3) bond length. As(1) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form AsO4 tetrahedra that share corners with two equivalent U(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 31-39°. The As(1)-O(4) bond length is 1.74 Å. The As(1)-O(5) bond length is 1.73 Å. The As(1)-O(6) bond length is 1.70 Å. The As(1)-O(7) bond length is 1.72 Å. There are eight inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one U(1) and one Bi(2) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Bi(2) and two equivalent Bi(1) atoms. In the third O site, O(3) is bonded to two equivalent Bi(1) and two equivalent Bi(2) atoms to form edge-sharing OBi4 tetrahedra. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Bi(1) and one As(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Bi(1), one Bi(2), and one As(1) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one U(1) and one As(1) atom. In the seventh O site, O(7) is bonded in a bent 150 degrees geometry to one U(1) and one As(1) atom. In the eighth O site, O(8) is bonded in a bent 120 degrees geometry to one Bi(1) and one Bi(2) atom.