Zn4B2O7 crystallizes in the monoclinic C2 space group. There are six inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(1), one O(10), one O(2), and one O(9) atom to form corner-sharing ZnO4 tetrahedra. In the second Zn site, Zn(2) is bonded to one O(1), one O(3), one O(6), and one O(7) atom to form distorted corner-sharing ZnO4 tetrahedra. In the third Zn site, Zn(3) is bonded to one O(1), one O(5), one O(7), and one O(8) atom to form corner-sharing ZnO4 tetrahedra. In the fourth Zn site, Zn(4) is bonded in a trigonal planar geometry to one O(11), one O(5), and one O(6) atom. In the fifth Zn site, Zn(5) is bonded to one O(11), one O(2), one O(4), and one O(8) atom to form corner-sharing ZnO4 tetrahedra. In the sixth Zn site, Zn(6) is bonded to one O(11), one O(3), one O(4), and one O(9) atom to form corner-sharing ZnO4 tetrahedra. There are four inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(2), one O(4), and one O(5) atom. In the second B site, B(2) is bonded in a linear geometry to two equivalent O(3) atoms. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(6), one O(7), and one O(9) atom. In the fourth B site, B(4) is bonded in a trigonal planar geometry to one O(10) and two equivalent O(8) atoms. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Zn(1), one Zn(2), and one Zn(3) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Zn(1), one Zn(5), and one B(1) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Zn(2), one Zn(6), and one B(2) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Zn(5), one Zn(6), and one B(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Zn(3), one Zn(4), and one B(1) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Zn(2), one Zn(4), and one B(3) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Zn(2), one Zn(3), and one B(3) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Zn(3), one Zn(5), and one B(4) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Zn(1), one Zn(6), and one B(3) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to two equivalent Zn(1) and one B(4) atom. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Zn(4), one Zn(5), and one Zn(6) atom.
Zn4B2O7 crystallizes in the monoclinic C2 space group. There are six inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to one O(1), one O(10), one O(2), and one O(9) atom to form corner-sharing ZnO4 tetrahedra. The Zn(1)-O(1) bond length is 1.93 Å. The Zn(1)-O(10) bond length is 1.99 Å. The Zn(1)-O(2) bond length is 2.01 Å. The Zn(1)-O(9) bond length is 2.01 Å. In the second Zn site, Zn(2) is bonded to one O(1), one O(3), one O(6), and one O(7) atom to form distorted corner-sharing ZnO4 tetrahedra. The Zn(2)-O(1) bond length is 1.89 Å. The Zn(2)-O(3) bond length is 2.18 Å. The Zn(2)-O(6) bond length is 1.98 Å. The Zn(2)-O(7) bond length is 1.98 Å. In the third Zn site, Zn(3) is bonded to one O(1), one O(5), one O(7), and one O(8) atom to form corner-sharing ZnO4 tetrahedra. The Zn(3)-O(1) bond length is 1.91 Å. The Zn(3)-O(5) bond length is 2.04 Å. The Zn(3)-O(7) bond length is 2.03 Å. The Zn(3)-O(8) bond length is 1.96 Å. In the fourth Zn site, Zn(4) is bonded in a trigonal planar geometry to one O(11), one O(5), and one O(6) atom. The Zn(4)-O(11) bond length is 1.85 Å. The Zn(4)-O(5) bond length is 1.92 Å. The Zn(4)-O(6) bond length is 1.94 Å. In the fifth Zn site, Zn(5) is bonded to one O(11), one O(2), one O(4), and one O(8) atom to form corner-sharing ZnO4 tetrahedra. The Zn(5)-O(11) bond length is 1.93 Å. The Zn(5)-O(2) bond length is 1.99 Å. The Zn(5)-O(4) bond length is 2.02 Å. The Zn(5)-O(8) bond length is 1.99 Å. In the sixth Zn site, Zn(6) is bonded to one O(11), one O(3), one O(4), and one O(9) atom to form corner-sharing ZnO4 tetrahedra. The Zn(6)-O(11) bond length is 1.91 Å. The Zn(6)-O(3) bond length is 2.21 Å. The Zn(6)-O(4) bond length is 1.96 Å. The Zn(6)-O(9) bond length is 1.93 Å. There are four inequivalent B sites. In the first B site, B(1) is bonded in a trigonal planar geometry to one O(2), one O(4), and one O(5) atom. The B(1)-O(2) bond length is 1.38 Å. The B(1)-O(4) bond length is 1.39 Å. The B(1)-O(5) bond length is 1.39 Å. In the second B site, B(2) is bonded in a linear geometry to two equivalent O(3) atoms. Both B(2)-O(3) bond lengths are 1.27 Å. In the third B site, B(3) is bonded in a trigonal planar geometry to one O(6), one O(7), and one O(9) atom. The B(3)-O(6) bond length is 1.39 Å. The B(3)-O(7) bond length is 1.38 Å. The B(3)-O(9) bond length is 1.38 Å. In the fourth B site, B(4) is bonded in a trigonal planar geometry to one O(10) and two equivalent O(8) atoms. The B(4)-O(10) bond length is 1.39 Å. Both B(4)-O(8) bond lengths are 1.39 Å. There are eleven inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to one Zn(1), one Zn(2), and one Zn(3) atom. In the second O site, O(2) is bonded in a trigonal planar geometry to one Zn(1), one Zn(5), and one B(1) atom. In the third O site, O(3) is bonded in a distorted trigonal non-coplanar geometry to one Zn(2), one Zn(6), and one B(2) atom. In the fourth O site, O(4) is bonded in a trigonal planar geometry to one Zn(5), one Zn(6), and one B(1) atom. In the fifth O site, O(5) is bonded in a distorted trigonal planar geometry to one Zn(3), one Zn(4), and one B(1) atom. In the sixth O site, O(6) is bonded in a trigonal planar geometry to one Zn(2), one Zn(4), and one B(3) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one Zn(2), one Zn(3), and one B(3) atom. In the eighth O site, O(8) is bonded in a trigonal planar geometry to one Zn(3), one Zn(5), and one B(4) atom. In the ninth O site, O(9) is bonded in a trigonal planar geometry to one Zn(1), one Zn(6), and one B(3) atom. In the tenth O site, O(10) is bonded in a trigonal planar geometry to two equivalent Zn(1) and one B(4) atom. In the eleventh O site, O(11) is bonded in a trigonal planar geometry to one Zn(4), one Zn(5), and one Zn(6) atom.