Fe2(HPO3)3 crystallizes in the hexagonal P6_3/m space group. Fe(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form FeO6 octahedra that share corners with six equivalent P(1)HO3 tetrahedra and  a faceface with one Fe(1)O6 octahedra. P(1) is bonded to one H(1), one O(2), and two equivalent O(1) atoms to form distorted PHO3 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-48°. H(1) is bonded in a single-bond geometry to one P(1) atom. There are two inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Fe(1) and one P(1) atom.
Fe2(HPO3)3 crystallizes in the hexagonal P6_3/m space group. Fe(1) is bonded to three equivalent O(1) and three equivalent O(2) atoms to form FeO6 octahedra that share corners with six equivalent P(1)HO3 tetrahedra and  a faceface with one Fe(1)O6 octahedra. All Fe(1)-O(1) bond lengths are 1.95 Å. All Fe(1)-O(2) bond lengths are 2.12 Å. P(1) is bonded to one H(1), one O(2), and two equivalent O(1) atoms to form distorted PHO3 tetrahedra that share corners with four equivalent Fe(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 36-48°. The P(1)-H(1) bond length is 1.41 Å. The P(1)-O(2) bond length is 1.56 Å. Both P(1)-O(1) bond lengths are 1.53 Å. H(1) is bonded in a single-bond geometry to one P(1) atom. There are two inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Fe(1) and one P(1) atom. In the second O site, O(2) is bonded in a 3-coordinate geometry to two equivalent Fe(1) and one P(1) atom.