LiH2PO4 crystallizes in the orthorhombic Pna2_1 space group. Li(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form LiO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra and corners with four equivalent P(1)O4 tetrahedra. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with four equivalent Li(1)O4 tetrahedra. There are two inequivalent H sites. In the first H site, H(1) is bonded in a linear geometry to one O(3) and one O(4) atom. In the second H site, H(2) is bonded in a distorted single-bond geometry to one O(2) and one O(4) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to two equivalent Li(1) and one P(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one P(1), and one H(2) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(1), one P(1), and one H(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one P(1), one H(1), and one H(2) atom.
LiH2PO4 crystallizes in the orthorhombic Pna2_1 space group. Li(1) is bonded to one O(2), one O(3), and two equivalent O(1) atoms to form LiO4 tetrahedra that share corners with two equivalent Li(1)O4 tetrahedra and corners with four equivalent P(1)O4 tetrahedra. The Li(1)-O(2) bond length is 2.01 Å. The Li(1)-O(3) bond length is 1.98 Å. There is one shorter (1.98 Å) and one longer (1.99 Å) Li(1)-O(1) bond length. P(1) is bonded to one O(1), one O(2), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with four equivalent Li(1)O4 tetrahedra. The P(1)-O(1) bond length is 1.51 Å. The P(1)-O(2) bond length is 1.61 Å. The P(1)-O(3) bond length is 1.52 Å. The P(1)-O(4) bond length is 1.60 Å. There are two inequivalent H sites. In the first H site, H(1) is bonded in a linear geometry to one O(3) and one O(4) atom. The H(1)-O(3) bond length is 1.53 Å. The H(1)-O(4) bond length is 1.04 Å. In the second H site, H(2) is bonded in a distorted single-bond geometry to one O(2) and one O(4) atom. The H(2)-O(2) bond length is 1.01 Å. The H(2)-O(4) bond length is 1.65 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a trigonal planar geometry to two equivalent Li(1) and one P(1) atom. In the second O site, O(2) is bonded in a distorted trigonal planar geometry to one Li(1), one P(1), and one H(2) atom. In the third O site, O(3) is bonded in a trigonal planar geometry to one Li(1), one P(1), and one H(1) atom. In the fourth O site, O(4) is bonded in a distorted trigonal planar geometry to one P(1), one H(1), and one H(2) atom.