U8Pb3 crystallizes in the orthorhombic Pmn2_1 space group. There are six inequivalent U sites. In the first U site, U(1) is bonded in a 5-coordinate geometry to two equivalent U(4), four equivalent U(3), one Pb(1), one Pb(2), and one Pb(3) atom. In the second U site, U(2) is bonded in a 6-coordinate geometry to two equivalent U(3), two equivalent U(4), one Pb(2), one Pb(3), and two equivalent Pb(1) atoms. In the third U site, U(3) is bonded in a 11-coordinate geometry to one U(2), two equivalent U(1), two equivalent U(3), two equivalent U(5), one Pb(1), one Pb(2), and two equivalent Pb(3) atoms. In the fourth U site, U(4) is bonded in a 6-coordinate geometry to one U(1), one U(2), one U(6), one Pb(1), and two equivalent Pb(2) atoms. In the fifth U site, U(5) is bonded in a 3-coordinate geometry to four equivalent U(3) and one Pb(1) atom. In the sixth U site, U(6) is bonded in a 6-coordinate geometry to two equivalent U(4), one Pb(1), one Pb(3), and two equivalent Pb(2) atoms. There are three inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a 12-coordinate geometry to one U(1), one U(5), one U(6), two equivalent U(2), two equivalent U(3), two equivalent U(4), one Pb(2), and two equivalent Pb(3) atoms. In the second Pb site, Pb(2) is bonded in a 11-coordinate geometry to one U(1), one U(2), two equivalent U(3), two equivalent U(6), four equivalent U(4), and one Pb(1) atom. In the third Pb site, Pb(3) is bonded in a 7-coordinate geometry to one U(1), one U(2), one U(6), four equivalent U(3), and two equivalent Pb(1) atoms.
U8Pb3 crystallizes in the orthorhombic Pmn2_1 space group. There are six inequivalent U sites. In the first U site, U(1) is bonded in a 5-coordinate geometry to two equivalent U(4), four equivalent U(3), one Pb(1), one Pb(2), and one Pb(3) atom. Both U(1)-U(4) bond lengths are 2.61 Å. There are two shorter (3.30 Å) and two longer (3.41 Å) U(1)-U(3) bond lengths. The U(1)-Pb(1) bond length is 3.35 Å. The U(1)-Pb(2) bond length is 3.29 Å. The U(1)-Pb(3) bond length is 3.30 Å. In the second U site, U(2) is bonded in a 6-coordinate geometry to two equivalent U(3), two equivalent U(4), one Pb(2), one Pb(3), and two equivalent Pb(1) atoms. Both U(2)-U(3) bond lengths are 3.50 Å. Both U(2)-U(4) bond lengths are 2.55 Å. The U(2)-Pb(2) bond length is 3.16 Å. The U(2)-Pb(3) bond length is 3.20 Å. Both U(2)-Pb(1) bond lengths are 3.52 Å. In the third U site, U(3) is bonded in a 11-coordinate geometry to one U(2), two equivalent U(1), two equivalent U(3), two equivalent U(5), one Pb(1), one Pb(2), and two equivalent Pb(3) atoms. There is one shorter (2.90 Å) and one longer (3.27 Å) U(3)-U(3) bond length. There is one shorter (2.63 Å) and one longer (3.39 Å) U(3)-U(5) bond length. The U(3)-Pb(1) bond length is 3.26 Å. The U(3)-Pb(2) bond length is 3.22 Å. There is one shorter (3.24 Å) and one longer (3.28 Å) U(3)-Pb(3) bond length. In the fourth U site, U(4) is bonded in a 6-coordinate geometry to one U(1), one U(2), one U(6), one Pb(1), and two equivalent Pb(2) atoms. The U(4)-U(6) bond length is 2.62 Å. The U(4)-Pb(1) bond length is 3.53 Å. There is one shorter (3.34 Å) and one longer (3.42 Å) U(4)-Pb(2) bond length. In the fifth U site, U(5) is bonded in a 3-coordinate geometry to four equivalent U(3) and one Pb(1) atom. The U(5)-Pb(1) bond length is 3.42 Å. In the sixth U site, U(6) is bonded in a 6-coordinate geometry to two equivalent U(4), one Pb(1), one Pb(3), and two equivalent Pb(2) atoms. The U(6)-Pb(1) bond length is 3.14 Å. The U(6)-Pb(3) bond length is 3.13 Å. Both U(6)-Pb(2) bond lengths are 3.28 Å. There are three inequivalent Pb sites. In the first Pb site, Pb(1) is bonded in a 12-coordinate geometry to one U(1), one U(5), one U(6), two equivalent U(2), two equivalent U(3), two equivalent U(4), one Pb(2), and two equivalent Pb(3) atoms. The Pb(1)-Pb(2) bond length is 3.37 Å. Both Pb(1)-Pb(3) bond lengths are 3.44 Å. In the second Pb site, Pb(2) is bonded in a 11-coordinate geometry to one U(1), one U(2), two equivalent U(3), two equivalent U(6), four equivalent U(4), and one Pb(1) atom. In the third Pb site, Pb(3) is bonded in a 7-coordinate geometry to one U(1), one U(2), one U(6), four equivalent U(3), and two equivalent Pb(1) atoms.