HgB4O7 crystallizes in the orthorhombic Pmn2_1 space group. Hg(1) is bonded in a distorted pentagonal planar geometry to one O(4), two equivalent O(1), and two equivalent O(2) atoms. 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(4) atom to form corner-sharing BO4 tetrahedra. In the second B site, B(2) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form corner-sharing BO4 tetrahedra. There are four inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Hg(1), one B(1), and one B(2) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Hg(1), one B(1), and one B(2) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one B(1) and two equivalent B(2) atoms. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Hg(1) and two equivalent B(1) atoms.
HgB4O7 crystallizes in the orthorhombic Pmn2_1 space group. Hg(1) is bonded in a distorted pentagonal planar geometry to one O(4), two equivalent O(1), and two equivalent O(2) atoms. The Hg(1)-O(4) bond length is 2.42 Å. Both Hg(1)-O(1) bond lengths are 2.57 Å. Both Hg(1)-O(2) bond lengths are 2.46 Å. 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(4) atom to form corner-sharing BO4 tetrahedra. The B(1)-O(1) bond length is 1.46 Å. The B(1)-O(2) bond length is 1.47 Å. The B(1)-O(3) bond length is 1.56 Å. The B(1)-O(4) bond length is 1.45 Å. In the second B site, B(2) is bonded to one O(1), one O(2), and two equivalent O(3) atoms to form corner-sharing BO4 tetrahedra. The B(2)-O(1) bond length is 1.43 Å. The B(2)-O(2) bond length is 1.45 Å. There is one shorter (1.53 Å) and one longer (1.55 Å) B(2)-O(3) bond length. There are four inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one Hg(1), one B(1), and one B(2) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to one Hg(1), one B(1), and one B(2) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one B(1) and two equivalent B(2) atoms. In the fourth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Hg(1) and two equivalent B(1) atoms.