CsMg6BO8 crystallizes in the tetragonal P4/mmm space group. Cs(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form CsO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Cs(1)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1) and four equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Cs(1)O6 octahedra, corners with four equivalent Mg(1)O6 octahedra, edges with four equivalent Mg(2)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. In the second Mg site, Mg(2) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form a mixture of corner and edge-sharing MgO6 octahedra. The corner-sharing octahedra are not tilted. In the third Mg site, Mg(3) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted MgO6 octahedra that share corners with six equivalent Mg(3)O6 octahedra, edges with two equivalent Cs(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. B(1) is bonded in a square co-planar geometry to four equivalent O(3) atoms. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Cs(1), one Mg(1), and four equivalent Mg(3) atoms to form OCsMg5 octahedra that share corners with six equivalent O(1)CsMg5 octahedra, edges with four equivalent O(3)Cs2Mg2B2 octahedra, edges with four equivalent O(4)Mg6 octahedra, and edges with four equivalent O(2)Mg5 square pyramids. The corner-sharing octahedral tilt angles range from 0-3°. In the second O site, O(2) is bonded to one Mg(2) and four equivalent Mg(3) atoms to form OMg5 square pyramids that share corners with four equivalent O(3)Cs2Mg2B2 octahedra, corners with five equivalent O(2)Mg5 square pyramids, edges with four equivalent O(1)CsMg5 octahedra, and edges with four equivalent O(4)Mg6 octahedra. The corner-sharing octahedral tilt angles are 92°. In the third O site, O(3) is bonded to two equivalent Cs(1), two equivalent Mg(3), and two equivalent B(1) atoms to form distorted OCs2Mg2B2 octahedra that share corners with two equivalent O(4)Mg6 octahedra, corners with four equivalent O(3)Cs2Mg2B2 octahedra, corners with four equivalent O(2)Mg5 square pyramids, edges with four equivalent O(3)Cs2Mg2B2 octahedra, and edges with four equivalent O(1)CsMg5 octahedra. The corner-sharing octahedra are not tilted. In the fourth O site, O(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), and two equivalent Mg(3) atoms to form OMg6 octahedra that share corners with two equivalent O(3)Cs2Mg2B2 octahedra, corners with four equivalent O(4)Mg6 octahedra, edges with four equivalent O(1)CsMg5 octahedra, edges with four equivalent O(4)Mg6 octahedra, and edges with four equivalent O(2)Mg5 square pyramids. The corner-sharing octahedra are not tilted.
CsMg6BO8 crystallizes in the tetragonal P4/mmm space group. Cs(1) is bonded to two equivalent O(1) and four equivalent O(3) atoms to form CsO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with four equivalent Cs(1)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. Both Cs(1)-O(1) bond lengths are 2.80 Å. All Cs(1)-O(3) bond lengths are 2.21 Å. There are three inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1) and four equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Cs(1)O6 octahedra, corners with four equivalent Mg(1)O6 octahedra, edges with four equivalent Mg(2)O6 octahedra, and edges with eight equivalent Mg(3)O6 octahedra. The corner-sharing octahedra are not tilted. Both Mg(1)-O(1) bond lengths are 2.04 Å. All Mg(1)-O(4) bond lengths are 2.21 Å. In the second Mg site, Mg(2) is bonded to two equivalent O(2) and four equivalent O(4) atoms to form a mixture of corner and edge-sharing MgO6 octahedra. The corner-sharing octahedra are not tilted. Both Mg(2)-O(2) bond lengths are 2.15 Å. All Mg(2)-O(4) bond lengths are 2.21 Å. In the third Mg site, Mg(3) is bonded to one O(3), one O(4), two equivalent O(1), and two equivalent O(2) atoms to form distorted MgO6 octahedra that share corners with six equivalent Mg(3)O6 octahedra, edges with two equivalent Cs(1)O6 octahedra, edges with two equivalent Mg(1)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra, and edges with four equivalent Mg(3)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. The Mg(3)-O(3) bond length is 2.74 Å. The Mg(3)-O(4) bond length is 2.09 Å. Both Mg(3)-O(1) bond lengths are 2.21 Å. Both Mg(3)-O(2) bond lengths are 2.21 Å. B(1) is bonded in a square co-planar geometry to four equivalent O(3) atoms. All B(1)-O(3) bond lengths are 2.21 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Cs(1), one Mg(1), and four equivalent Mg(3) atoms to form OCsMg5 octahedra that share corners with six equivalent O(1)CsMg5 octahedra, edges with four equivalent O(3)Cs2Mg2B2 octahedra, edges with four equivalent O(4)Mg6 octahedra, and edges with four equivalent O(2)Mg5 square pyramids. The corner-sharing octahedral tilt angles range from 0-3°. In the second O site, O(2) is bonded to one Mg(2) and four equivalent Mg(3) atoms to form OMg5 square pyramids that share corners with four equivalent O(3)Cs2Mg2B2 octahedra, corners with five equivalent O(2)Mg5 square pyramids, edges with four equivalent O(1)CsMg5 octahedra, and edges with four equivalent O(4)Mg6 octahedra. The corner-sharing octahedral tilt angles are 92°. In the third O site, O(3) is bonded to two equivalent Cs(1), two equivalent Mg(3), and two equivalent B(1) atoms to form distorted OCs2Mg2B2 octahedra that share corners with two equivalent O(4)Mg6 octahedra, corners with four equivalent O(3)Cs2Mg2B2 octahedra, corners with four equivalent O(2)Mg5 square pyramids, edges with four equivalent O(3)Cs2Mg2B2 octahedra, and edges with four equivalent O(1)CsMg5 octahedra. The corner-sharing octahedra are not tilted. In the fourth O site, O(4) is bonded to two equivalent Mg(1), two equivalent Mg(2), and two equivalent Mg(3) atoms to form OMg6 octahedra that share corners with two equivalent O(3)Cs2Mg2B2 octahedra, corners with four equivalent O(4)Mg6 octahedra, edges with four equivalent O(1)CsMg5 octahedra, edges with four equivalent O(4)Mg6 octahedra, and edges with four equivalent O(2)Mg5 square pyramids. The corner-sharing octahedra are not tilted.