UOsB4 crystallizes in the orthorhombic Cmmm space group. U(1) is bonded in a 18-coordinate geometry to four equivalent Os(1), two equivalent B(3), four equivalent B(2), and eight equivalent B(1) atoms. Os(1) is bonded in a 15-coordinate geometry to four equivalent U(1), one Os(1), two equivalent B(2), four equivalent B(1), and four equivalent B(3) atoms. There are three inequivalent B sites. In the first B site, B(1) is bonded in a 9-coordinate geometry to four equivalent U(1), two equivalent Os(1), one B(1), one B(2), and one B(3) atom. In the second B site, B(2) is bonded in a 9-coordinate geometry to four equivalent U(1), two equivalent Os(1), one B(2), and two equivalent B(1) atoms. In the third B site, B(3) is bonded in a 9-coordinate geometry to two equivalent U(1), four equivalent Os(1), one B(3), and two equivalent B(1) atoms.
UOsB4 crystallizes in the orthorhombic Cmmm space group. U(1) is bonded in a 18-coordinate geometry to four equivalent Os(1), two equivalent B(3), four equivalent B(2), and eight equivalent B(1) atoms. There are two shorter (2.96 Å) and two longer (3.16 Å) U(1)-Os(1) bond lengths. Both U(1)-B(3) bond lengths are 2.65 Å. All U(1)-B(2) bond lengths are 2.74 Å. There are four shorter (2.73 Å) and four longer (2.76 Å) U(1)-B(1) bond lengths. Os(1) is bonded in a 15-coordinate geometry to four equivalent U(1), one Os(1), two equivalent B(2), four equivalent B(1), and four equivalent B(3) atoms. The Os(1)-Os(1) bond length is 2.81 Å. Both Os(1)-B(2) bond lengths are 2.25 Å. All Os(1)-B(1) bond lengths are 2.34 Å. All Os(1)-B(3) bond lengths are 2.42 Å. There are three inequivalent B sites. In the first B site, B(1) is bonded in a 9-coordinate geometry to four equivalent U(1), two equivalent Os(1), one B(1), one B(2), and one B(3) atom. The B(1)-B(1) bond length is 1.77 Å. The B(1)-B(2) bond length is 1.89 Å. The B(1)-B(3) bond length is 1.76 Å. In the second B site, B(2) is bonded in a 9-coordinate geometry to four equivalent U(1), two equivalent Os(1), one B(2), and two equivalent B(1) atoms. The B(2)-B(2) bond length is 1.78 Å. In the third B site, B(3) is bonded in a 9-coordinate geometry to two equivalent U(1), four equivalent Os(1), one B(3), and two equivalent B(1) atoms. The B(3)-B(3) bond length is 1.75 Å.