Be3As2(H2O5)2 crystallizes in the monoclinic C2/c space group. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded to one O(1), one O(3), and two equivalent O(4) atoms to form BeO4 tetrahedra that share corners with two equivalent Be(1)O4 tetrahedra and corners with four equivalent As(1)O4 tetrahedra. In the second Be site, Be(2) is bonded to two equivalent O(2) and two equivalent O(5) atoms to form BeO4 tetrahedra that share corners with two equivalent As(1)O4 tetrahedra. As(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form AsO4 tetrahedra that share  a cornercorner with one Be(2)O4 tetrahedra and corners with four equivalent Be(1)O4 tetrahedra. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(1) and one O(5) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(5) atom. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Be(1), one As(1), and one H(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Be(2) and one As(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Be(1) and one As(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to two equivalent Be(1) and one As(1) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Be(2), one H(1), and one H(2) atom.
Be3As2(H2O5)2 crystallizes in the monoclinic C2/c space group. There are two inequivalent Be sites. In the first Be site, Be(1) is bonded to one O(1), one O(3), and two equivalent O(4) atoms to form BeO4 tetrahedra that share corners with two equivalent Be(1)O4 tetrahedra and corners with four equivalent As(1)O4 tetrahedra. The Be(1)-O(1) bond length is 1.65 Å. The Be(1)-O(3) bond length is 1.59 Å. There is one shorter (1.67 Å) and one longer (1.68 Å) Be(1)-O(4) bond length. In the second Be site, Be(2) is bonded to two equivalent O(2) and two equivalent O(5) atoms to form BeO4 tetrahedra that share corners with two equivalent As(1)O4 tetrahedra. Both Be(2)-O(2) bond lengths are 1.61 Å. Both Be(2)-O(5) bond lengths are 1.66 Å. As(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form AsO4 tetrahedra that share  a cornercorner with one Be(2)O4 tetrahedra and corners with four equivalent Be(1)O4 tetrahedra. The As(1)-O(1) bond length is 1.71 Å. The As(1)-O(2) bond length is 1.70 Å. The As(1)-O(3) bond length is 1.70 Å. The As(1)-O(4) bond length is 1.76 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(1) and one O(5) atom. The H(1)-O(1) bond length is 1.72 Å. The H(1)-O(5) bond length is 1.00 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(5) atom. The H(2)-O(5) bond length is 0.98 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Be(1), one As(1), and one H(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one Be(2) and one As(1) atom. In the third O site, O(3) is bonded in a bent 120 degrees geometry to one Be(1) and one As(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to two equivalent Be(1) and one As(1) atom. In the fifth O site, O(5) is bonded in a trigonal planar geometry to one Be(2), one H(1), and one H(2) atom.