Ba3Nb6Si4O26 crystallizes in the hexagonal P-62m space group. Ba(1) is bonded in a 12-coordinate geometry to two equivalent O(1), two equivalent O(5), and eight equivalent O(2) atoms. Nb(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(5) atoms to form NbO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 7-32°. Si(1) is bonded to one O(3) and three equivalent O(2) atoms to form SiO4 tetrahedra that share corners with three equivalent Nb(1)O6 octahedra and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 32°. There are five inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to two equivalent Ba(1) and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(1), one Nb(1), and one Si(1) atom. In the third O site, O(3) is bonded in a linear geometry to two equivalent Si(1) atoms. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Nb(1) atoms. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Ba(1) and two equivalent Nb(1) atoms.
Ba3Nb6Si4O26 crystallizes in the hexagonal P-62m space group. Ba(1) is bonded in a 12-coordinate geometry to two equivalent O(1), two equivalent O(5), and eight equivalent O(2) atoms. Both Ba(1)-O(1) bond lengths are 3.15 Å. Both Ba(1)-O(5) bond lengths are 2.90 Å. There are four shorter (2.89 Å) and four longer (2.98 Å) Ba(1)-O(2) bond lengths. Nb(1) is bonded to one O(1), one O(4), two equivalent O(2), and two equivalent O(5) atoms to form NbO6 octahedra that share corners with four equivalent Nb(1)O6 octahedra and corners with two equivalent Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 7-32°. The Nb(1)-O(1) bond length is 2.00 Å. The Nb(1)-O(4) bond length is 1.94 Å. Both Nb(1)-O(2) bond lengths are 2.07 Å. Both Nb(1)-O(5) bond lengths are 1.96 Å. Si(1) is bonded to one O(3) and three equivalent O(2) atoms to form SiO4 tetrahedra that share corners with three equivalent Nb(1)O6 octahedra and  a cornercorner with one Si(1)O4 tetrahedra. The corner-sharing octahedral tilt angles are 32°. The Si(1)-O(3) bond length is 1.60 Å. All Si(1)-O(2) bond lengths are 1.62 Å. There are five inequivalent O sites. In the first O site, O(1) is bonded in a linear geometry to two equivalent Ba(1) and two equivalent Nb(1) atoms. In the second O site, O(2) is bonded in a distorted bent 150 degrees geometry to two equivalent Ba(1), one Nb(1), and one Si(1) atom. In the third O site, O(3) is bonded in a linear geometry to two equivalent Si(1) atoms. In the fourth O site, O(4) is bonded in a bent 150 degrees geometry to two equivalent Nb(1) atoms. In the fifth O site, O(5) is bonded in a distorted bent 150 degrees geometry to one Ba(1) and two equivalent Nb(1) atoms.