U2NiAs2(H2O3)6(H2O)6 crystallizes in the triclinic P-1 space group. The structure consists of six water molecules inside a U2NiAs2(H2O3)6 framework. In the U2NiAs2(H2O3)6 framework, U(1) is bonded to one O(1), one O(11), one O(4), one O(5), one O(7), and one O(8) atom to form UO6 octahedra that share corners with four equivalent As(1)O4 tetrahedra. Ni(1) is bonded in an octahedral geometry to two equivalent O(10), two equivalent O(12), and two equivalent O(9) atoms. As(1) is bonded to one O(1), one O(11), one O(5), and one O(8) atom to form AsO4 tetrahedra that share corners with four equivalent U(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-48°. There are six inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(10) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(12) atom. In the third H site, H(3) is bonded in a single-bond geometry to one O(9) atom. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(9) atom. In the fifth H site, H(8) is bonded in a single-bond geometry to one O(10) atom. In the sixth H site, H(10) is bonded in a distorted single-bond geometry to one O(12) and one O(4) atom. There are nine inequivalent O sites. In the first O site, O(4) is bonded in a bent 150 degrees geometry to one U(1) and one H(10) atom. In the second O site, O(5) is bonded in a bent 150 degrees geometry to one U(1) and one As(1) atom. In the third O site, O(7) is bonded in a single-bond geometry to one U(1) atom. In the fourth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one U(1) and one As(1) atom. In the fifth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Ni(1), one H(3), and one H(4) atom. In the sixth O site, O(10) is bonded in a distorted water-like geometry to one Ni(1), one H(1), and one H(8) atom. In the seventh O site, O(11) is bonded in a 2-coordinate geometry to one U(1) and one As(1) atom. In the eighth O site, O(12) is bonded in a distorted trigonal non-coplanar geometry to one Ni(1), one H(10), and one H(2) atom. In the ninth O site, O(1) is bonded in a 2-coordinate geometry to one U(1) and one As(1) atom.
U2NiAs2(H2O3)6(H2O)6 crystallizes in the triclinic P-1 space group. The structure consists of six water molecules inside a U2NiAs2(H2O3)6 framework. In the U2NiAs2(H2O3)6 framework, U(1) is bonded to one O(1), one O(11), one O(4), one O(5), one O(7), and one O(8) atom to form UO6 octahedra that share corners with four equivalent As(1)O4 tetrahedra. The U(1)-O(1) bond length is 2.29 Å. The U(1)-O(11) bond length is 2.31 Å. The U(1)-O(4) bond length is 1.84 Å. The U(1)-O(5) bond length is 2.25 Å. The U(1)-O(7) bond length is 1.82 Å. The U(1)-O(8) bond length is 2.29 Å. Ni(1) is bonded in an octahedral geometry to two equivalent O(10), two equivalent O(12), and two equivalent O(9) atoms. Both Ni(1)-O(10) bond lengths are 2.22 Å. Both Ni(1)-O(12) bond lengths are 2.07 Å. Both Ni(1)-O(9) bond lengths are 2.08 Å. As(1) is bonded to one O(1), one O(11), one O(5), and one O(8) atom to form AsO4 tetrahedra that share corners with four equivalent U(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-48°. The As(1)-O(1) bond length is 1.72 Å. The As(1)-O(11) bond length is 1.72 Å. The As(1)-O(5) bond length is 1.71 Å. The As(1)-O(8) bond length is 1.72 Å. There are six inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(10) atom. The H(1)-O(10) bond length is 0.99 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(12) atom. The H(2)-O(12) bond length is 0.99 Å. In the third H site, H(3) is bonded in a single-bond geometry to one O(9) atom. The H(3)-O(9) bond length is 0.99 Å. In the fourth H site, H(4) is bonded in a single-bond geometry to one O(9) atom. The H(4)-O(9) bond length is 1.00 Å. In the fifth H site, H(8) is bonded in a single-bond geometry to one O(10) atom. The H(8)-O(10) bond length is 1.01 Å. In the sixth H site, H(10) is bonded in a distorted single-bond geometry to one O(12) and one O(4) atom. The H(10)-O(12) bond length is 1.00 Å. The H(10)-O(4) bond length is 1.65 Å. There are nine inequivalent O sites. In the first O site, O(4) is bonded in a bent 150 degrees geometry to one U(1) and one H(10) atom. In the second O site, O(5) is bonded in a bent 150 degrees geometry to one U(1) and one As(1) atom. In the third O site, O(7) is bonded in a single-bond geometry to one U(1) atom. In the fourth O site, O(8) is bonded in a distorted bent 120 degrees geometry to one U(1) and one As(1) atom. In the fifth O site, O(9) is bonded in a distorted trigonal non-coplanar geometry to one Ni(1), one H(3), and one H(4) atom. In the sixth O site, O(10) is bonded in a distorted water-like geometry to one Ni(1), one H(1), and one H(8) atom. In the seventh O site, O(11) is bonded in a 2-coordinate geometry to one U(1) and one As(1) atom. In the eighth O site, O(12) is bonded in a distorted trigonal non-coplanar geometry to one Ni(1), one H(10), and one H(2) atom. In the ninth O site, O(1) is bonded in a 2-coordinate geometry to one U(1) and one As(1) atom.