Co2AsO5 crystallizes in the orthorhombic Pnnm space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form CoO6 octahedra that share corners with four equivalent As(1)O4 tetrahedra, corners with four equivalent Co(2)O5 trigonal bipyramids, and edges with two equivalent Co(1)O6 octahedra. In the second Co site, Co(2) is bonded to one O(1), two equivalent O(3), and two equivalent O(4) atoms to form distorted CoO5 trigonal bipyramids that share corners with four equivalent Co(1)O6 octahedra, corners with four equivalent As(1)O4 tetrahedra, and  an edgeedge with one Co(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 52-57°. As(1) is bonded to one O(2), one O(3), and two equivalent O(4) atoms to form AsO4 tetrahedra that share corners with four equivalent Co(1)O6 octahedra and corners with four equivalent Co(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 57-68°. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Co(2) and two equivalent Co(1) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to two equivalent Co(1) and one As(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Co(2) and one As(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Co(1), one Co(2), and one As(1) atom.
Co2AsO5 crystallizes in the orthorhombic Pnnm space group. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form CoO6 octahedra that share corners with four equivalent As(1)O4 tetrahedra, corners with four equivalent Co(2)O5 trigonal bipyramids, and edges with two equivalent Co(1)O6 octahedra. Both Co(1)-O(1) bond lengths are 1.89 Å. Both Co(1)-O(2) bond lengths are 2.02 Å. Both Co(1)-O(4) bond lengths are 2.28 Å. In the second Co site, Co(2) is bonded to one O(1), two equivalent O(3), and two equivalent O(4) atoms to form distorted CoO5 trigonal bipyramids that share corners with four equivalent Co(1)O6 octahedra, corners with four equivalent As(1)O4 tetrahedra, and  an edgeedge with one Co(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 52-57°. The Co(2)-O(1) bond length is 1.92 Å. There is one shorter (1.97 Å) and one longer (2.11 Å) Co(2)-O(3) bond length. Both Co(2)-O(4) bond lengths are 2.00 Å. As(1) is bonded to one O(2), one O(3), and two equivalent O(4) atoms to form AsO4 tetrahedra that share corners with four equivalent Co(1)O6 octahedra and corners with four equivalent Co(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 57-68°. The As(1)-O(2) bond length is 1.76 Å. The As(1)-O(3) bond length is 1.72 Å. Both As(1)-O(4) bond lengths are 1.72 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Co(2) and two equivalent Co(1) atoms. In the second O site, O(2) is bonded in a trigonal planar geometry to two equivalent Co(1) and one As(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Co(2) and one As(1) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Co(1), one Co(2), and one As(1) atom.