VHSe2O7NH4 crystallizes in the monoclinic P2_1/m space group. The structure consists of two ammonium molecules inside a VHSe2O7 framework. In the VHSe2O7 framework, V(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. H(1) is bonded in a linear geometry to two equivalent O(3) atoms. Se(1) is bonded in a trigonal non-coplanar geometry to one O(1), one O(2), and one O(3) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one V(1) and one Se(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one V(1) and one Se(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one H(1) and one Se(1) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to two equivalent V(1) atoms.
VHSe2O7NH4 crystallizes in the monoclinic P2_1/m space group. The structure consists of two ammonium molecules inside a VHSe2O7 framework. In the VHSe2O7 framework, V(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. Both V(1)-O(1) bond lengths are 2.03 Å. Both V(1)-O(2) bond lengths are 2.01 Å. There is one shorter (1.68 Å) and one longer (2.38 Å) V(1)-O(4) bond length. H(1) is bonded in a linear geometry to two equivalent O(3) atoms. Both H(1)-O(3) bond lengths are 1.22 Å. Se(1) is bonded in a trigonal non-coplanar geometry to one O(1), one O(2), and one O(3) atom. The Se(1)-O(1) bond length is 1.74 Å. The Se(1)-O(2) bond length is 1.74 Å. The Se(1)-O(3) bond length is 1.74 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a bent 120 degrees geometry to one V(1) and one Se(1) atom. In the second O site, O(2) is bonded in a bent 120 degrees geometry to one V(1) and one Se(1) atom. In the third O site, O(3) is bonded in a distorted bent 120 degrees geometry to one H(1) and one Se(1) atom. In the fourth O site, O(4) is bonded in a distorted linear geometry to two equivalent V(1) atoms.