MgCoAsO5 crystallizes in the orthorhombic P2_12_12_1 space group. Mg(1) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(4), and one O(5) atom. Co(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(5) atoms to form CoO6 octahedra that share corners with four equivalent As(1)O4 tetrahedra and edges with two equivalent Co(1)O6 octahedra. 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 corners with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-64°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Co(1) and one As(1) atom. In the second O site, O(2) is bonded in a water-like geometry to one Mg(1) and one As(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Co(1), and one As(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Mg(1), one Co(1), and one As(1) atom. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one Mg(1) and two equivalent Co(1) atoms.
MgCoAsO5 crystallizes in the orthorhombic P2_12_12_1 space group. Mg(1) is bonded in a 4-coordinate geometry to one O(2), one O(3), one O(4), and one O(5) atom. The Mg(1)-O(2) bond length is 2.10 Å. The Mg(1)-O(3) bond length is 2.10 Å. The Mg(1)-O(4) bond length is 2.11 Å. The Mg(1)-O(5) bond length is 2.04 Å. Co(1) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(5) atoms to form CoO6 octahedra that share corners with four equivalent As(1)O4 tetrahedra and edges with two equivalent Co(1)O6 octahedra. The Co(1)-O(3) bond length is 2.06 Å. The Co(1)-O(4) bond length is 2.06 Å. There is one shorter (2.06 Å) and one longer (2.07 Å) Co(1)-O(1) bond length. There is one shorter (1.84 Å) and one longer (1.88 Å) Co(1)-O(5) bond length. 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 corners with four equivalent Co(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 37-64°. The As(1)-O(1) bond length is 1.74 Å. The As(1)-O(2) bond length is 1.71 Å. The As(1)-O(3) bond length is 1.72 Å. The As(1)-O(4) bond length is 1.72 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a 3-coordinate geometry to two equivalent Co(1) and one As(1) atom. In the second O site, O(2) is bonded in a water-like geometry to one Mg(1) and one As(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to one Mg(1), one Co(1), and one As(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Mg(1), one Co(1), and one As(1) atom. In the fifth O site, O(5) is bonded in a trigonal non-coplanar geometry to one Mg(1) and two equivalent Co(1) atoms.