Zn2(OH)PO4 crystallizes in the orthorhombic Pnnm space group. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form ZnO6 octahedra that share corners with four equivalent P(1)O4 tetrahedra, corners with four equivalent Zn(2)O5 trigonal bipyramids, and edges with two equivalent Zn(1)O6 octahedra. In the second Zn site, Zn(2) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form ZnO5 trigonal bipyramids that share corners with four equivalent Zn(1)O6 octahedra, corners with four equivalent P(1)O4 tetrahedra, and  an edgeedge with one Zn(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 57-72°. P(1) is bonded to one O(3), one O(4), and two equivalent O(2) atoms to form PO4 tetrahedra that share corners with four equivalent Zn(1)O6 octahedra and corners with four equivalent Zn(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 55-61°. H(1) is bonded in a single-bond geometry to one O(1) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Zn(2), two equivalent Zn(1), and one H(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Zn(1), one Zn(2), and one P(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Zn(2) and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to two equivalent Zn(1) and one P(1) atom.
Zn2(OH)PO4 crystallizes in the orthorhombic Pnnm space group. There are two inequivalent Zn sites. In the first Zn site, Zn(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form ZnO6 octahedra that share corners with four equivalent P(1)O4 tetrahedra, corners with four equivalent Zn(2)O5 trigonal bipyramids, and edges with two equivalent Zn(1)O6 octahedra. Both Zn(1)-O(1) bond lengths are 2.05 Å. Both Zn(1)-O(2) bond lengths are 2.32 Å. Both Zn(1)-O(4) bond lengths are 2.08 Å. In the second Zn site, Zn(2) is bonded to one O(1), two equivalent O(2), and two equivalent O(3) atoms to form ZnO5 trigonal bipyramids that share corners with four equivalent Zn(1)O6 octahedra, corners with four equivalent P(1)O4 tetrahedra, and  an edgeedge with one Zn(2)O5 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 57-72°. The Zn(2)-O(1) bond length is 2.02 Å. Both Zn(2)-O(2) bond lengths are 2.08 Å. There is one shorter (2.06 Å) and one longer (2.07 Å) Zn(2)-O(3) bond length. P(1) is bonded to one O(3), one O(4), and two equivalent O(2) atoms to form PO4 tetrahedra that share corners with four equivalent Zn(1)O6 octahedra and corners with four equivalent Zn(2)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles range from 55-61°. The P(1)-O(3) bond length is 1.57 Å. The P(1)-O(4) bond length is 1.57 Å. Both P(1)-O(2) bond lengths are 1.56 Å. H(1) is bonded in a single-bond geometry to one O(1) atom. The H(1)-O(1) bond length is 0.98 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one Zn(2), two equivalent Zn(1), and one H(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Zn(1), one Zn(2), and one P(1) atom. In the third O site, O(3) is bonded in a distorted trigonal planar geometry to two equivalent Zn(2) and one P(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to two equivalent Zn(1) and one P(1) atom.