FeCoBi2(AsO6)2 crystallizes in the triclinic P-1 space group. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(10), two equivalent O(11), and two equivalent O(8) atoms to form FeO6 octahedra that share corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra, and edges with two equivalent Co(2)O6 octahedra. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(12), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra, and edges with two equivalent Co(1)O6 octahedra. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms to form CoO6 octahedra that share corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra, and edges with two equivalent Fe(2)O6 octahedra. In the second Co site, Co(2) is bonded to two equivalent O(11), two equivalent O(7), and two equivalent O(8) atoms to form CoO6 octahedra that share corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra, and edges with two equivalent Fe(1)O6 octahedra. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 6-coordinate geometry to one O(10), one O(5), one O(7), one O(9), and two equivalent O(2) atoms. In the second Bi site, Bi(2) is bonded in a 6-coordinate geometry to one O(12), one O(2), one O(3), one O(4), and two equivalent O(5) atoms. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(10), one O(7), and one O(9) atom to form AsO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Co(1)O6 octahedra, and  a cornercorner with one Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-63°. In the second As site, As(2) is bonded to one O(12), one O(3), one O(4), and one O(8) atom to form AsO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Co(1)O6 octahedra, and  a cornercorner with one Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-62°. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Fe(2), one Co(1), and one As(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Bi(2) and two equivalent Bi(1) atoms. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Bi(2) and one As(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Co(1), one Bi(2), and one As(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Bi(1) and two equivalent Bi(2) atoms. In the sixth O site, O(6) is bonded in a water-like geometry to one Fe(2) and one Co(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Co(2), one Bi(1), and one As(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Fe(1), one Co(2), and one As(2) atom. In the ninth O site, O(9) is bonded in a distorted bent 120 degrees geometry to one Bi(1) and one As(1) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Fe(1), one Bi(1), and one As(1) atom. In the eleventh O site, O(11) is bonded in a distorted water-like geometry to one Fe(1) and one Co(2) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Fe(2), one Bi(2), and one As(2) atom.
FeCoBi2(AsO6)2 crystallizes in the triclinic P-1 space group. There are two inequivalent Fe sites. In the first Fe site, Fe(1) is bonded to two equivalent O(10), two equivalent O(11), and two equivalent O(8) atoms to form FeO6 octahedra that share corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra, and edges with two equivalent Co(2)O6 octahedra. Both Fe(1)-O(10) bond lengths are 2.01 Å. Both Fe(1)-O(11) bond lengths are 2.04 Å. Both Fe(1)-O(8) bond lengths are 2.04 Å. In the second Fe site, Fe(2) is bonded to two equivalent O(1), two equivalent O(12), and two equivalent O(6) atoms to form FeO6 octahedra that share corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra, and edges with two equivalent Co(1)O6 octahedra. Both Fe(2)-O(1) bond lengths are 2.05 Å. Both Fe(2)-O(12) bond lengths are 1.99 Å. Both Fe(2)-O(6) bond lengths are 1.88 Å. There are two inequivalent Co sites. In the first Co site, Co(1) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(6) atoms to form CoO6 octahedra that share corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra, and edges with two equivalent Fe(2)O6 octahedra. Both Co(1)-O(1) bond lengths are 2.13 Å. Both Co(1)-O(4) bond lengths are 1.95 Å. Both Co(1)-O(6) bond lengths are 1.89 Å. In the second Co site, Co(2) is bonded to two equivalent O(11), two equivalent O(7), and two equivalent O(8) atoms to form CoO6 octahedra that share corners with two equivalent As(1)O4 tetrahedra, corners with two equivalent As(2)O4 tetrahedra, and edges with two equivalent Fe(1)O6 octahedra. Both Co(2)-O(11) bond lengths are 1.76 Å. Both Co(2)-O(7) bond lengths are 2.01 Å. Both Co(2)-O(8) bond lengths are 2.15 Å. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 6-coordinate geometry to one O(10), one O(5), one O(7), one O(9), and two equivalent O(2) atoms. The Bi(1)-O(10) bond length is 2.62 Å. The Bi(1)-O(5) bond length is 2.42 Å. The Bi(1)-O(7) bond length is 2.51 Å. The Bi(1)-O(9) bond length is 2.28 Å. There is one shorter (2.18 Å) and one longer (2.29 Å) Bi(1)-O(2) bond length. In the second Bi site, Bi(2) is bonded in a 6-coordinate geometry to one O(12), one O(2), one O(3), one O(4), and two equivalent O(5) atoms. The Bi(2)-O(12) bond length is 2.61 Å. The Bi(2)-O(2) bond length is 2.42 Å. The Bi(2)-O(3) bond length is 2.27 Å. The Bi(2)-O(4) bond length is 2.55 Å. There is one shorter (2.17 Å) and one longer (2.29 Å) Bi(2)-O(5) bond length. There are two inequivalent As sites. In the first As site, As(1) is bonded to one O(1), one O(10), one O(7), and one O(9) atom to form AsO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Co(1)O6 octahedra, and  a cornercorner with one Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 46-63°. The As(1)-O(1) bond length is 1.73 Å. The As(1)-O(10) bond length is 1.73 Å. The As(1)-O(7) bond length is 1.73 Å. The As(1)-O(9) bond length is 1.70 Å. In the second As site, As(2) is bonded to one O(12), one O(3), one O(4), and one O(8) atom to form AsO4 tetrahedra that share  a cornercorner with one Fe(1)O6 octahedra,  a cornercorner with one Fe(2)O6 octahedra,  a cornercorner with one Co(1)O6 octahedra, and  a cornercorner with one Co(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 47-62°. The As(2)-O(12) bond length is 1.73 Å. The As(2)-O(3) bond length is 1.70 Å. The As(2)-O(4) bond length is 1.74 Å. The As(2)-O(8) bond length is 1.72 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal planar geometry to one Fe(2), one Co(1), and one As(1) atom. In the second O site, O(2) is bonded in a distorted T-shaped geometry to one Bi(2) and two equivalent Bi(1) atoms. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Bi(2) and one As(2) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one Co(1), one Bi(2), and one As(2) atom. In the fifth O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Bi(1) and two equivalent Bi(2) atoms. In the sixth O site, O(6) is bonded in a water-like geometry to one Fe(2) and one Co(1) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Co(2), one Bi(1), and one As(1) atom. In the eighth O site, O(8) is bonded in a 3-coordinate geometry to one Fe(1), one Co(2), and one As(2) atom. In the ninth O site, O(9) is bonded in a distorted bent 120 degrees geometry to one Bi(1) and one As(1) atom. In the tenth O site, O(10) is bonded in a distorted trigonal planar geometry to one Fe(1), one Bi(1), and one As(1) atom. In the eleventh O site, O(11) is bonded in a distorted water-like geometry to one Fe(1) and one Co(2) atom. In the twelfth O site, O(12) is bonded in a distorted trigonal planar geometry to one Fe(2), one Bi(2), and one As(2) atom.