CoBiAsO5 crystallizes in the triclinic P-1 space group. Co(1) is bonded to one O(1), one O(2), one O(4), one O(5), and two equivalent O(3) atoms to form CoO6 octahedra that share  a cornercorner with one Bi(1)O5 square pyramid, corners with four equivalent As(1)O4 tetrahedra,  an edgeedge with one Co(1)O6 octahedra, and edges with three equivalent Bi(1)O5 square pyramids. Bi(1) is bonded to one O(2), one O(4), one O(5), and two equivalent O(3) atoms to form distorted BiO5 square pyramids that share  a cornercorner with one Co(1)O6 octahedra, corners with three equivalent As(1)O4 tetrahedra, edges with three equivalent Co(1)O6 octahedra, and  an edgeedge with one Bi(1)O5 square pyramid. The corner-sharing octahedral tilt angles are 39°. As(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form AsO4 tetrahedra that share corners with four equivalent Co(1)O6 octahedra and corners with three equivalent Bi(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 50-56°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Co(1) and one As(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Co(1), one Bi(1), and one As(1) atom. In the third O site, O(3) is bonded to two equivalent Co(1) and two equivalent Bi(1) atoms to form edge-sharing OCo2Bi2 tetrahedra. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Co(1), one Bi(1), and one As(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Co(1), one Bi(1), and one As(1) atom.
CoBiAsO5 crystallizes in the triclinic P-1 space group. Co(1) is bonded to one O(1), one O(2), one O(4), one O(5), and two equivalent O(3) atoms to form CoO6 octahedra that share  a cornercorner with one Bi(1)O5 square pyramid, corners with four equivalent As(1)O4 tetrahedra,  an edgeedge with one Co(1)O6 octahedra, and edges with three equivalent Bi(1)O5 square pyramids. The Co(1)-O(1) bond length is 2.05 Å. The Co(1)-O(2) bond length is 2.12 Å. The Co(1)-O(4) bond length is 2.22 Å. The Co(1)-O(5) bond length is 2.13 Å. There is one shorter (2.10 Å) and one longer (2.19 Å) Co(1)-O(3) bond length. Bi(1) is bonded to one O(2), one O(4), one O(5), and two equivalent O(3) atoms to form distorted BiO5 square pyramids that share  a cornercorner with one Co(1)O6 octahedra, corners with three equivalent As(1)O4 tetrahedra, edges with three equivalent Co(1)O6 octahedra, and  an edgeedge with one Bi(1)O5 square pyramid. The corner-sharing octahedral tilt angles are 39°. The Bi(1)-O(2) bond length is 2.36 Å. The Bi(1)-O(4) bond length is 2.41 Å. The Bi(1)-O(5) bond length is 2.35 Å. There is one shorter (2.15 Å) and one longer (2.30 Å) Bi(1)-O(3) bond length. As(1) is bonded to one O(1), one O(2), one O(4), and one O(5) atom to form AsO4 tetrahedra that share corners with four equivalent Co(1)O6 octahedra and corners with three equivalent Bi(1)O5 square pyramids. The corner-sharing octahedral tilt angles range from 50-56°. The As(1)-O(1) bond length is 1.71 Å. The As(1)-O(2) bond length is 1.73 Å. The As(1)-O(4) bond length is 1.75 Å. The As(1)-O(5) bond length is 1.73 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Co(1) and one As(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Co(1), one Bi(1), and one As(1) atom. In the third O site, O(3) is bonded to two equivalent Co(1) and two equivalent Bi(1) atoms to form edge-sharing OCo2Bi2 tetrahedra. In the fourth O site, O(4) is bonded in a 3-coordinate geometry to one Co(1), one Bi(1), and one As(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Co(1), one Bi(1), and one As(1) atom.