SiPO4(OH) crystallizes in the monoclinic P2_1/c space group. Si(1) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(2) atoms to form SiO6 octahedra that share corners with two equivalent Si(1)O6 octahedra and corners with four equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 38°. P(1) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form PO4 tetrahedra that share corners with four equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-40°. H(1) is bonded in a single-bond geometry to one O(2) atom. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1) and one P(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Si(1) and one H(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one P(1) atom.
SiPO4(OH) crystallizes in the monoclinic P2_1/c space group. Si(1) is bonded to one O(1), one O(3), one O(4), one O(5), and two equivalent O(2) atoms to form SiO6 octahedra that share corners with two equivalent Si(1)O6 octahedra and corners with four equivalent P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 38°. The Si(1)-O(1) bond length is 1.74 Å. The Si(1)-O(3) bond length is 1.78 Å. The Si(1)-O(4) bond length is 1.80 Å. The Si(1)-O(5) bond length is 1.75 Å. Both Si(1)-O(2) bond lengths are 1.84 Å. P(1) is bonded to one O(1), one O(3), one O(4), and one O(5) atom to form PO4 tetrahedra that share corners with four equivalent Si(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 38-40°. The P(1)-O(1) bond length is 1.54 Å. The P(1)-O(3) bond length is 1.54 Å. The P(1)-O(4) bond length is 1.54 Å. The P(1)-O(5) bond length is 1.54 Å. H(1) is bonded in a single-bond geometry to one O(2) atom. The H(1)-O(2) bond length is 0.99 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Si(1) and one P(1) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Si(1) and one H(1) atom. In the third O site, O(3) is bonded in a bent 150 degrees geometry to one Si(1) and one P(1) atom. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to one Si(1) and one P(1) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one P(1) atom.