NaInSi2O6 is Esseneite structured and crystallizes in the monoclinic C2/c space group. Na(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. In(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form InO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra and edges with two equivalent In(1)O6 octahedra. Si(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with three equivalent In(1)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-59°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Na(1), one In(1), and one Si(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Na(1) and two equivalent Si(1) atoms. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), two equivalent In(1), and one Si(1) atom.
NaInSi2O6 is Esseneite structured and crystallizes in the monoclinic C2/c space group. Na(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(3) atoms. Both Na(1)-O(1) bond lengths are 2.39 Å. Both Na(1)-O(2) bond lengths are 2.55 Å. Both Na(1)-O(3) bond lengths are 2.52 Å. In(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form InO6 octahedra that share corners with six equivalent Si(1)O4 tetrahedra and edges with two equivalent In(1)O6 octahedra. Both In(1)-O(1) bond lengths are 2.11 Å. There are two shorter (2.18 Å) and two longer (2.26 Å) In(1)-O(3) bond lengths. Si(1) is bonded to one O(1), one O(3), and two equivalent O(2) atoms to form SiO4 tetrahedra that share corners with three equivalent In(1)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 36-59°. The Si(1)-O(1) bond length is 1.61 Å. The Si(1)-O(3) bond length is 1.65 Å. Both Si(1)-O(2) bond lengths are 1.67 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a distorted T-shaped geometry to one Na(1), one In(1), and one Si(1) atom. In the second O site, O(2) is bonded in a 2-coordinate geometry to one Na(1) and two equivalent Si(1) atoms. In the third O site, O(3) is bonded in a 4-coordinate geometry to one Na(1), two equivalent In(1), and one Si(1) atom.