RhSi2P3O13 crystallizes in the trigonal P321 space group. Rh(1) is bonded to three equivalent O(3) and three equivalent O(4) atoms to form RhO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(5) and three equivalent O(1) atoms to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra and corners with three equivalent P(1)O4 tetrahedra. In the second Si site, Si(2) is bonded to one O(5) and three equivalent O(2) atoms to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. There are two inequivalent P sites. In the first P site, P(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with two equivalent Rh(1)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. In the second P site, P(2) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with two equivalent Rh(1)O6 octahedra and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. There are five inequivalent O sites. In the first O site, O(5) is bonded in a linear geometry to one Si(1) and one Si(2) atom. In the second O site, O(1) is bonded in a bent 120 degrees geometry to one Si(1) and one P(1) atom. In the third O site, O(2) is bonded in a linear geometry to one Si(2) and one P(2) atom. In the fourth O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Rh(1) and one P(1) atom. In the fifth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Rh(1) and one P(2) atom.
RhSi2P3O13 crystallizes in the trigonal P321 space group. Rh(1) is bonded to three equivalent O(3) and three equivalent O(4) atoms to form RhO6 octahedra that share corners with three equivalent P(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. All Rh(1)-O(3) bond lengths are 2.05 Å. All Rh(1)-O(4) bond lengths are 2.05 Å. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(5) and three equivalent O(1) atoms to form SiO4 tetrahedra that share  a cornercorner with one Si(2)O4 tetrahedra and corners with three equivalent P(1)O4 tetrahedra. The Si(1)-O(5) bond length is 1.61 Å. All Si(1)-O(1) bond lengths are 1.64 Å. In the second Si site, Si(2) is bonded to one O(5) and three equivalent O(2) atoms to form SiO4 tetrahedra that share  a cornercorner with one Si(1)O4 tetrahedra and corners with three equivalent P(2)O4 tetrahedra. The Si(2)-O(5) bond length is 1.62 Å. All Si(2)-O(2) bond lengths are 1.62 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with two equivalent Rh(1)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 51°. Both P(1)-O(1) bond lengths are 1.59 Å. Both P(1)-O(3) bond lengths are 1.52 Å. In the second P site, P(2) is bonded to two equivalent O(2) and two equivalent O(4) atoms to form PO4 tetrahedra that share corners with two equivalent Rh(1)O6 octahedra and corners with two equivalent Si(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 52°. Both P(2)-O(2) bond lengths are 1.57 Å. Both P(2)-O(4) bond lengths are 1.52 Å. There are five inequivalent O sites. In the first O site, O(5) is bonded in a linear geometry to one Si(1) and one Si(2) atom. In the second O site, O(1) is bonded in a bent 120 degrees geometry to one Si(1) and one P(1) atom. In the third O site, O(2) is bonded in a linear geometry to one Si(2) and one P(2) atom. In the fourth O site, O(3) is bonded in a distorted bent 120 degrees geometry to one Rh(1) and one P(1) atom. In the fifth O site, O(4) is bonded in a distorted bent 120 degrees geometry to one Rh(1) and one P(2) atom.