BaSiP4(HO7)2 crystallizes in the triclinic P-1 space group. Ba(1) is bonded in a 10-coordinate geometry to two equivalent O(2), two equivalent O(6), two equivalent O(7), and four equivalent O(1) atoms. Si(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form SiO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra and corners with four equivalent P(1)O4 tetrahedra. There are two inequivalent P sites. In the first P site, 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 two equivalent Si(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 37-42°. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Si(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 39°. H(1) is bonded in a linear geometry to one O(6) and one O(7) atom. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Si(1), and one P(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 120 degrees geometry to one P(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Ba(1), one P(2), and one H(1) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Ba(1), one P(2), and one H(1) atom.
BaSiP4(HO7)2 crystallizes in the triclinic P-1 space group. Ba(1) is bonded in a 10-coordinate geometry to two equivalent O(2), two equivalent O(6), two equivalent O(7), and four equivalent O(1) atoms. Both Ba(1)-O(2) bond lengths are 3.21 Å. Both Ba(1)-O(6) bond lengths are 2.91 Å. Both Ba(1)-O(7) bond lengths are 3.33 Å. There are two shorter (2.73 Å) and two longer (2.86 Å) Ba(1)-O(1) bond lengths. Si(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(5) atoms to form SiO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra and corners with four equivalent P(1)O4 tetrahedra. Both Si(1)-O(2) bond lengths are 1.80 Å. Both Si(1)-O(3) bond lengths are 1.76 Å. Both Si(1)-O(5) bond lengths are 1.79 Å. There are two inequivalent P sites. In the first P site, 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 two equivalent Si(1)O6 octahedra and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 37-42°. The P(1)-O(1) bond length is 1.51 Å. The P(1)-O(2) bond length is 1.55 Å. The P(1)-O(3) bond length is 1.53 Å. The P(1)-O(4) bond length is 1.62 Å. In the second P site, P(2) is bonded to one O(4), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Si(1)O6 octahedra and  a cornercorner with one P(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 39°. The P(2)-O(4) bond length is 1.60 Å. The P(2)-O(5) bond length is 1.53 Å. The P(2)-O(6) bond length is 1.51 Å. The P(2)-O(7) bond length is 1.57 Å. H(1) is bonded in a linear geometry to one O(6) and one O(7) atom. The H(1)-O(6) bond length is 1.54 Å. The H(1)-O(7) bond length is 1.04 Å. There are seven inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to two equivalent Ba(1) and one P(1) atom. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to one Ba(1), one Si(1), and one P(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 120 degrees geometry to one P(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Si(1) and one P(2) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one Ba(1), one P(2), and one H(1) atom. In the seventh O site, O(7) is bonded in a bent 120 degrees geometry to one Ba(1), one P(2), and one H(1) atom.