BiAsO5 crystallizes in the orthorhombic P2_12_12_1 space group. Bi(1) is bonded to one O(4), one O(5), two equivalent O(1), and two equivalent O(2) atoms to form BiO6 octahedra that share corners with four equivalent As(1)O4 tetrahedra and edges with two equivalent Bi(1)O6 octahedra. As(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form AsO4 tetrahedra that share corners with four equivalent Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-59°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to two equivalent Bi(1) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Bi(1) and one As(1) atom. In the third O site, O(3) is bonded in a single-bond geometry to one As(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Bi(1) and one As(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Bi(1) and one As(1) atom.
BiAsO5 crystallizes in the orthorhombic P2_12_12_1 space group. Bi(1) is bonded to one O(4), one O(5), two equivalent O(1), and two equivalent O(2) atoms to form BiO6 octahedra that share corners with four equivalent As(1)O4 tetrahedra and edges with two equivalent Bi(1)O6 octahedra. The Bi(1)-O(4) bond length is 2.16 Å. The Bi(1)-O(5) bond length is 2.17 Å. There is one shorter (2.10 Å) and one longer (2.11 Å) Bi(1)-O(1) bond length. There is one shorter (2.27 Å) and one longer (2.30 Å) Bi(1)-O(2) bond length. As(1) is bonded to one O(2), one O(3), one O(4), and one O(5) atom to form AsO4 tetrahedra that share corners with four equivalent Bi(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 43-59°. The As(1)-O(2) bond length is 1.84 Å. The As(1)-O(3) bond length is 1.65 Å. The As(1)-O(4) bond length is 1.76 Å. The As(1)-O(5) bond length is 1.76 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a water-like geometry to two equivalent Bi(1) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Bi(1) and one As(1) atom. In the third O site, O(3) is bonded in a single-bond geometry to one As(1) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Bi(1) and one As(1) atom. In the fifth O site, O(5) is bonded in a bent 120 degrees geometry to one Bi(1) and one As(1) atom.