B2Bi2O7 crystallizes in the triclinic P-1 space group. There are two inequivalent B sites. In the first B site, B(1) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form BO4 tetrahedra that share corners with two equivalent Bi(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-58°. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(4), one O(5), and one O(6) atom. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), one O(7), and two equivalent O(1) atoms. In the second Bi site, Bi(2) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(7) atoms to form BiO6 octahedra that share corners with two equivalent B(1)O4 tetrahedra and  an edgeedge with one Bi(2)O6 octahedra. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one B(1) and two equivalent Bi(1) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to one B(1), one Bi(1), and one Bi(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one B(1), one Bi(1), and one Bi(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one B(2) and one Bi(2) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one B(2), one Bi(1), and one Bi(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one B(1) and one B(2) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Bi(1) and two equivalent Bi(2) atoms.
B2Bi2O7 crystallizes in the triclinic P-1 space group. There are two inequivalent B sites. In the first B site, B(1) is bonded to one O(1), one O(2), one O(3), and one O(6) atom to form BO4 tetrahedra that share corners with two equivalent Bi(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 50-58°. The B(1)-O(1) bond length is 1.46 Å. The B(1)-O(2) bond length is 1.51 Å. The B(1)-O(3) bond length is 1.51 Å. The B(1)-O(6) bond length is 1.52 Å. In the second B site, B(2) is bonded in a trigonal planar geometry to one O(4), one O(5), and one O(6) atom. The B(2)-O(4) bond length is 1.38 Å. The B(2)-O(5) bond length is 1.42 Å. The B(2)-O(6) bond length is 1.38 Å. There are two inequivalent Bi sites. In the first Bi site, Bi(1) is bonded in a 6-coordinate geometry to one O(2), one O(3), one O(5), one O(7), and two equivalent O(1) atoms. The Bi(1)-O(2) bond length is 2.48 Å. The Bi(1)-O(3) bond length is 2.39 Å. The Bi(1)-O(5) bond length is 2.36 Å. The Bi(1)-O(7) bond length is 2.35 Å. There is one shorter (2.31 Å) and one longer (2.37 Å) Bi(1)-O(1) bond length. In the second Bi site, Bi(2) is bonded to one O(2), one O(3), one O(4), one O(5), and two equivalent O(7) atoms to form BiO6 octahedra that share corners with two equivalent B(1)O4 tetrahedra and  an edgeedge with one Bi(2)O6 octahedra. The Bi(2)-O(2) bond length is 2.16 Å. The Bi(2)-O(3) bond length is 2.14 Å. The Bi(2)-O(4) bond length is 2.12 Å. The Bi(2)-O(5) bond length is 2.25 Å. There is one shorter (2.16 Å) and one longer (2.20 Å) Bi(2)-O(7) bond length. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one B(1) and two equivalent Bi(1) atoms. In the second O site, O(2) is bonded in a 3-coordinate geometry to one B(1), one Bi(1), and one Bi(2) atom. In the third O site, O(3) is bonded in a 3-coordinate geometry to one B(1), one Bi(1), and one Bi(2) atom. In the fourth O site, O(4) is bonded in a distorted bent 150 degrees geometry to one B(2) and one Bi(2) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one B(2), one Bi(1), and one Bi(2) atom. In the sixth O site, O(6) is bonded in a bent 150 degrees geometry to one B(1) and one B(2) atom. In the seventh O site, O(7) is bonded in a distorted T-shaped geometry to one Bi(1) and two equivalent Bi(2) atoms.