LiScSi2O6 crystallizes in the monoclinic P2_1/c space group. Li(1) is bonded to one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted LiO5 square pyramids that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with three equivalent Sc(1)O6 octahedra, and  an edgeedge with one Si(2)O4 tetrahedra. Sc(1) is bonded to one O(2), one O(4), two equivalent O(3), and two equivalent O(6) atoms to form ScO6 octahedra that share corners with three equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, edges with two equivalent Sc(1)O6 octahedra, and edges with three equivalent Li(1)O5 square pyramids. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(6), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with three equivalent Sc(1)O6 octahedra, corners with two equivalent Li(1)O5 square pyramids, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 39-61°. In the second Si site, Si(2) is bonded to one O(3), one O(4), and two equivalent O(5) atoms to form SiO4 tetrahedra that share corners with three equivalent Sc(1)O6 octahedra, corners with two equivalent Li(1)O5 square pyramids, corners with two equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Li(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 32-60°. There are six inequivalent O sites. In the first O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Li(1) and two equivalent Si(2) atoms. In the second O site, O(6) is bonded to one Li(1), two equivalent Sc(1), and one Si(1) atom to form distorted corner-sharing OLiSc2Si trigonal pyramids. In the third O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the fourth O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Li(1), one Sc(1), and one Si(1) atom. In the fifth O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Li(1), two equivalent Sc(1), and one Si(2) atom. In the sixth O site, O(4) is bonded in a distorted T-shaped geometry to one Li(1), one Sc(1), and one Si(2) atom.
LiScSi2O6 crystallizes in the monoclinic P2_1/c space group. Li(1) is bonded to one O(2), one O(3), one O(4), one O(5), and one O(6) atom to form distorted LiO5 square pyramids that share corners with two equivalent Si(1)O4 tetrahedra, corners with two equivalent Si(2)O4 tetrahedra, edges with three equivalent Sc(1)O6 octahedra, and  an edgeedge with one Si(2)O4 tetrahedra. The Li(1)-O(2) bond length is 2.09 Å. The Li(1)-O(3) bond length is 2.09 Å. The Li(1)-O(4) bond length is 2.12 Å. The Li(1)-O(5) bond length is 2.55 Å. The Li(1)-O(6) bond length is 2.09 Å. Sc(1) is bonded to one O(2), one O(4), two equivalent O(3), and two equivalent O(6) atoms to form ScO6 octahedra that share corners with three equivalent Si(1)O4 tetrahedra, corners with three equivalent Si(2)O4 tetrahedra, edges with two equivalent Sc(1)O6 octahedra, and edges with three equivalent Li(1)O5 square pyramids. The Sc(1)-O(2) bond length is 2.02 Å. The Sc(1)-O(4) bond length is 2.01 Å. There is one shorter (2.12 Å) and one longer (2.27 Å) Sc(1)-O(3) bond length. There is one shorter (2.12 Å) and one longer (2.27 Å) Sc(1)-O(6) bond length. There are two inequivalent Si sites. In the first Si site, Si(1) is bonded to one O(2), one O(6), and two equivalent O(1) atoms to form SiO4 tetrahedra that share corners with three equivalent Sc(1)O6 octahedra, corners with two equivalent Li(1)O5 square pyramids, and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 39-61°. The Si(1)-O(2) bond length is 1.62 Å. The Si(1)-O(6) bond length is 1.66 Å. Both Si(1)-O(1) bond lengths are 1.65 Å. In the second Si site, Si(2) is bonded to one O(3), one O(4), and two equivalent O(5) atoms to form SiO4 tetrahedra that share corners with three equivalent Sc(1)O6 octahedra, corners with two equivalent Li(1)O5 square pyramids, corners with two equivalent Si(2)O4 tetrahedra, and  an edgeedge with one Li(1)O5 square pyramid. The corner-sharing octahedral tilt angles range from 32-60°. The Si(2)-O(3) bond length is 1.65 Å. The Si(2)-O(4) bond length is 1.62 Å. Both Si(2)-O(5) bond lengths are 1.65 Å. There are six inequivalent O sites. In the first O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Li(1) and two equivalent Si(2) atoms. In the second O site, O(6) is bonded to one Li(1), two equivalent Sc(1), and one Si(1) atom to form distorted corner-sharing OLiSc2Si trigonal pyramids. In the third O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Si(1) atoms. In the fourth O site, O(2) is bonded in a distorted trigonal non-coplanar geometry to one Li(1), one Sc(1), and one Si(1) atom. In the fifth O site, O(3) is bonded in a distorted rectangular see-saw-like geometry to one Li(1), two equivalent Sc(1), and one Si(2) atom. In the sixth O site, O(4) is bonded in a distorted T-shaped geometry to one Li(1), one Sc(1), and one Si(2) atom.