Ca2MgAs2(H2O5)2 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(4), two equivalent O(3), and two equivalent O(5) atoms. Mg(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with four equivalent As(1)O4 tetrahedra. As(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form AsO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. There are two inequivalent H sites. In the first H site, H(1) is bonded in a distorted bent 150 degrees geometry to one O(2) and one O(4) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(4) and one O(5) atom. There are five inequivalent O sites. In the first O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Ca(1), one As(1), and one H(2) atom. In the second O site, O(1) is bonded in a 3-coordinate geometry to one Ca(1), one Mg(1), and one As(1) atom. In the third O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one As(1), and one H(1) atom. In the fourth O site, O(3) is bonded to two equivalent Ca(1), one Mg(1), and one As(1) atom to form a mixture of distorted edge and corner-sharing OCa2MgAs tetrahedra. In the fifth O site, O(4) is bonded in a distorted water-like geometry to one Ca(1), one Mg(1), one H(1), and one H(2) atom.
Ca2MgAs2(H2O5)2 crystallizes in the monoclinic P2_1/c space group. Ca(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(4), two equivalent O(3), and two equivalent O(5) atoms. The Ca(1)-O(1) bond length is 2.43 Å. The Ca(1)-O(2) bond length is 2.36 Å. The Ca(1)-O(4) bond length is 2.42 Å. There is one shorter (2.48 Å) and one longer (2.52 Å) Ca(1)-O(3) bond length. There is one shorter (2.43 Å) and one longer (2.49 Å) Ca(1)-O(5) bond length. Mg(1) is bonded to two equivalent O(1), two equivalent O(3), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with four equivalent As(1)O4 tetrahedra. Both Mg(1)-O(1) bond lengths are 2.06 Å. Both Mg(1)-O(3) bond lengths are 2.18 Å. Both Mg(1)-O(4) bond lengths are 2.05 Å. As(1) is bonded to one O(1), one O(2), one O(3), and one O(5) atom to form AsO4 tetrahedra that share corners with two equivalent Mg(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 48-56°. The As(1)-O(1) bond length is 1.71 Å. The As(1)-O(2) bond length is 1.68 Å. The As(1)-O(3) bond length is 1.71 Å. The As(1)-O(5) bond length is 1.71 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a distorted bent 150 degrees geometry to one O(2) and one O(4) atom. The H(1)-O(2) bond length is 1.52 Å. The H(1)-O(4) bond length is 1.01 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(4) and one O(5) atom. The H(2)-O(4) bond length is 0.99 Å. The H(2)-O(5) bond length is 1.76 Å. There are five inequivalent O sites. In the first O site, O(5) is bonded in a 4-coordinate geometry to two equivalent Ca(1), one As(1), and one H(2) atom. In the second O site, O(1) is bonded in a 3-coordinate geometry to one Ca(1), one Mg(1), and one As(1) atom. In the third O site, O(2) is bonded in a distorted trigonal planar geometry to one Ca(1), one As(1), and one H(1) atom. In the fourth O site, O(3) is bonded to two equivalent Ca(1), one Mg(1), and one As(1) atom to form a mixture of distorted edge and corner-sharing OCa2MgAs tetrahedra. In the fifth O site, O(4) is bonded in a distorted water-like geometry to one Ca(1), one Mg(1), one H(1), and one H(2) atom.