Ba3As4(HO7)2 crystallizes in the monoclinic C2/c space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 8-coordinate geometry to two equivalent O(4), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(4), one O(6), one O(7), two equivalent O(3), and two equivalent O(5) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form corner-sharing AsO4 tetrahedra. In the second As site, As(2) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form corner-sharing AsO4 tetrahedra. H(1) is bonded in a single-bond geometry to one O(2) atom. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Ba(2), one As(1), and one As(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ba(2), one As(2), and one H(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Ba(2) and one As(1) atom. In the fourth O site, O(7) is bonded in a distorted single-bond geometry to one Ba(1), one Ba(2), and one As(2) atom. In the fifth O site, O(4) is bonded in a distorted single-bond geometry to one Ba(1), one Ba(2), and one As(1) atom. In the sixth O site, O(5) is bonded in a 1-coordinate geometry to one Ba(1), two equivalent Ba(2), and one As(1) atom. In the seventh O site, O(6) is bonded in a distorted trigonal planar geometry to one Ba(1), one Ba(2), and one As(2) atom.
Ba3As4(HO7)2 crystallizes in the monoclinic C2/c space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded in a 8-coordinate geometry to two equivalent O(4), two equivalent O(5), two equivalent O(6), and two equivalent O(7) atoms. Both Ba(1)-O(4) bond lengths are 2.83 Å. Both Ba(1)-O(5) bond lengths are 3.15 Å. Both Ba(1)-O(6) bond lengths are 2.80 Å. Both Ba(1)-O(7) bond lengths are 2.80 Å. In the second Ba site, Ba(2) is bonded in a 9-coordinate geometry to one O(1), one O(2), one O(4), one O(6), one O(7), two equivalent O(3), and two equivalent O(5) atoms. The Ba(2)-O(1) bond length is 3.16 Å. The Ba(2)-O(2) bond length is 2.85 Å. The Ba(2)-O(4) bond length is 3.02 Å. The Ba(2)-O(6) bond length is 2.76 Å. The Ba(2)-O(7) bond length is 3.05 Å. There is one shorter (2.69 Å) and one longer (2.80 Å) Ba(2)-O(3) bond length. There is one shorter (2.75 Å) and one longer (2.93 Å) Ba(2)-O(5) bond length. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form corner-sharing AsO4 tetrahedra. The As(1)-O(1) bond length is 1.88 Å. The As(1)-O(3) bond length is 1.69 Å. The As(1)-O(4) bond length is 1.70 Å. The As(1)-O(5) bond length is 1.71 Å. In the second As site, As(2) is bonded to one O(1), one O(2), one O(6), and one O(7) atom to form corner-sharing AsO4 tetrahedra. The As(2)-O(1) bond length is 1.77 Å. The As(2)-O(2) bond length is 1.78 Å. The As(2)-O(6) bond length is 1.69 Å. The As(2)-O(7) bond length is 1.69 Å. H(1) is bonded in a single-bond geometry to one O(2) atom. The H(1)-O(2) bond length is 1.00 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Ba(2), one As(1), and one As(2) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Ba(2), one As(2), and one H(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Ba(2) and one As(1) atom. In the fourth O site, O(7) is bonded in a distorted single-bond geometry to one Ba(1), one Ba(2), and one As(2) atom. In the fifth O site, O(4) is bonded in a distorted single-bond geometry to one Ba(1), one Ba(2), and one As(1) atom. In the sixth O site, O(5) is bonded in a 1-coordinate geometry to one Ba(1), two equivalent Ba(2), and one As(1) atom. In the seventh O site, O(6) is bonded in a distorted trigonal planar geometry to one Ba(1), one Ba(2), and one As(2) atom.