Cu2BiAsO6 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(2) and two equivalent O(3) atoms. In the second Cu site, Cu(2) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted CuO5 square pyramids that share corners with three equivalent As(1)O4 tetrahedra. Bi(1) is bonded in a 5-coordinate geometry to one O(4) and four equivalent O(3) atoms. As(1) is bonded to one O(1), one O(4), and two equivalent O(2) atoms to form AsO4 tetrahedra that share corners with three equivalent Cu(2)O5 square pyramids. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Cu(2) and one As(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(2), and one As(1) atom. In the third O site, O(3) is bonded to one Cu(1), one Cu(2), and two equivalent Bi(1) atoms to form a mixture of distorted corner and edge-sharing OCu2Bi2 tetrahedra. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Bi(1) and one As(1) atom.
Cu2BiAsO6 crystallizes in the orthorhombic Pnma space group. There are two inequivalent Cu sites. In the first Cu site, Cu(1) is bonded in a rectangular see-saw-like geometry to two equivalent O(2) and two equivalent O(3) atoms. Both Cu(1)-O(2) bond lengths are 2.00 Å. Both Cu(1)-O(3) bond lengths are 1.94 Å. In the second Cu site, Cu(2) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form distorted CuO5 square pyramids that share corners with three equivalent As(1)O4 tetrahedra. The Cu(2)-O(1) bond length is 2.50 Å. Both Cu(2)-O(2) bond lengths are 1.99 Å. Both Cu(2)-O(3) bond lengths are 1.93 Å. Bi(1) is bonded in a 5-coordinate geometry to one O(4) and four equivalent O(3) atoms. The Bi(1)-O(4) bond length is 2.33 Å. There are two shorter (2.28 Å) and two longer (2.45 Å) Bi(1)-O(3) bond lengths. As(1) is bonded to one O(1), one O(4), and two equivalent O(2) atoms to form AsO4 tetrahedra that share corners with three equivalent Cu(2)O5 square pyramids. The As(1)-O(1) bond length is 1.70 Å. The As(1)-O(4) bond length is 1.70 Å. Both As(1)-O(2) bond lengths are 1.77 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Cu(2) and one As(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Cu(1), one Cu(2), and one As(1) atom. In the third O site, O(3) is bonded to one Cu(1), one Cu(2), and two equivalent Bi(1) atoms to form a mixture of distorted corner and edge-sharing OCu2Bi2 tetrahedra. In the fourth O site, O(4) is bonded in a 2-coordinate geometry to one Bi(1) and one As(1) atom.