Th(As4O9)2 crystallizes in the monoclinic C2/c space group. Th(1) is bonded in a 8-coordinate geometry to two equivalent O(4), two equivalent O(5), two equivalent O(8), and two equivalent O(9) atoms. There are four inequivalent As sites. In the first As site, As(1) is bonded in a distorted T-shaped geometry to one O(3), one O(6), and one O(7) atom. In the second As site, As(2) is bonded in a distorted T-shaped geometry to one O(1), one O(2), and one O(7) atom. In the third As site, As(3) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(4), and one O(8) atom. In the fourth As site, As(4) is bonded in a tetrahedral geometry to one O(3), one O(5), one O(6), and one O(9) atom. There are nine inequivalent O sites. In the first O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Th(1) and one As(3) atom. In the second O site, O(1) is bonded in a bent 120 degrees geometry to one As(2) and one As(3) atom. In the third O site, O(9) is bonded in a distorted single-bond geometry to one Th(1) and one As(4) atom. In the fourth O site, O(2) is bonded in a bent 120 degrees geometry to one As(2) and one As(3) atom. In the fifth O site, O(3) is bonded in a bent 120 degrees geometry to one As(1) and one As(4) atom. In the sixth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Th(1) and one As(3) atom. In the seventh O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Th(1) and one As(4) atom. In the eighth O site, O(6) is bonded in a bent 120 degrees geometry to one As(1) and one As(4) atom. In the ninth O site, O(7) is bonded in a bent 120 degrees geometry to one As(1) and one As(2) atom.
Th(As4O9)2 crystallizes in the monoclinic C2/c space group. Th(1) is bonded in a 8-coordinate geometry to two equivalent O(4), two equivalent O(5), two equivalent O(8), and two equivalent O(9) atoms. Both Th(1)-O(4) bond lengths are 2.40 Å. Both Th(1)-O(5) bond lengths are 2.37 Å. Both Th(1)-O(8) bond lengths are 2.38 Å. Both Th(1)-O(9) bond lengths are 2.49 Å. There are four inequivalent As sites. In the first As site, As(1) is bonded in a distorted T-shaped geometry to one O(3), one O(6), and one O(7) atom. The As(1)-O(3) bond length is 1.83 Å. The As(1)-O(6) bond length is 1.82 Å. The As(1)-O(7) bond length is 1.78 Å. In the second As site, As(2) is bonded in a distorted T-shaped geometry to one O(1), one O(2), and one O(7) atom. The As(2)-O(1) bond length is 1.83 Å. The As(2)-O(2) bond length is 1.84 Å. The As(2)-O(7) bond length is 1.79 Å. In the third As site, As(3) is bonded in a tetrahedral geometry to one O(1), one O(2), one O(4), and one O(8) atom. The As(3)-O(1) bond length is 1.73 Å. The As(3)-O(2) bond length is 1.74 Å. The As(3)-O(4) bond length is 1.67 Å. The As(3)-O(8) bond length is 1.67 Å. In the fourth As site, As(4) is bonded in a tetrahedral geometry to one O(3), one O(5), one O(6), and one O(9) atom. The As(4)-O(3) bond length is 1.74 Å. The As(4)-O(5) bond length is 1.67 Å. The As(4)-O(6) bond length is 1.73 Å. The As(4)-O(9) bond length is 1.68 Å. There are nine inequivalent O sites. In the first O site, O(8) is bonded in a distorted bent 150 degrees geometry to one Th(1) and one As(3) atom. In the second O site, O(1) is bonded in a bent 120 degrees geometry to one As(2) and one As(3) atom. In the third O site, O(9) is bonded in a distorted single-bond geometry to one Th(1) and one As(4) atom. In the fourth O site, O(2) is bonded in a bent 120 degrees geometry to one As(2) and one As(3) atom. In the fifth O site, O(3) is bonded in a bent 120 degrees geometry to one As(1) and one As(4) atom. In the sixth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one Th(1) and one As(3) atom. In the seventh O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Th(1) and one As(4) atom. In the eighth O site, O(6) is bonded in a bent 120 degrees geometry to one As(1) and one As(4) atom. In the ninth O site, O(7) is bonded in a bent 120 degrees geometry to one As(1) and one As(2) atom.