CsMg14BO15 crystallizes in the orthorhombic Pmm2 space group. Cs(1) is bonded in a 5-coordinate geometry to one O(2), two equivalent O(10), and two equivalent O(6) atoms. There are ten inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(10) and two equivalent O(7) atoms to form distorted MgO4 tetrahedra that share corners with two equivalent Mg(8)O6 octahedra, corners with two equivalent Mg(9)O5 square pyramids, corners with two equivalent Mg(1)O4 tetrahedra, and corners with four equivalent Mg(3)O4 trigonal pyramids. The corner-sharing octahedral tilt angles are 70°. In the second Mg site, Mg(2) is bonded to one O(1), one O(2), two equivalent O(11), and two equivalent O(8) atoms to form MgO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, edges with four equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(10)O5 square pyramids, edges with two equivalent Mg(7)O5 square pyramids, and edges with two equivalent Mg(9)O5 square pyramids. The corner-sharing octahedral tilt angles are 2°. In the third Mg site, Mg(3) is bonded to one O(4), one O(6), and two equivalent O(10) atoms to form distorted MgO4 trigonal pyramids that share  a cornercorner with one Mg(4)O6 octahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with three equivalent Mg(3)O4 trigonal pyramids,  an edgeedge with one Mg(5)O6 octahedra, and edges with two equivalent Mg(9)O5 square pyramids. The corner-sharing octahedral tilt angles are 8°. In the fourth Mg site, Mg(4) is bonded to one O(4), one O(5), one O(8), one O(9), and two equivalent O(11) atoms to form MgO6 octahedra that share corners with four equivalent Mg(4)O6 octahedra,  a cornercorner with one Mg(3)O4 trigonal pyramid,  an edgeedge with one Mg(5)O6 octahedra,  an edgeedge with one Mg(8)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra,  an edgeedge with one Mg(7)O5 square pyramid, edges with two equivalent Mg(10)O5 square pyramids, and edges with two equivalent Mg(9)O5 square pyramids. The corner-sharing octahedral tilt angles range from 4-10°. In the fifth Mg site, Mg(5) is bonded to one O(6), one O(8), two equivalent O(1), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Mg(5)O6 octahedra,  a cornercorner with one Mg(7)O5 square pyramid, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with four equivalent Mg(9)O5 square pyramids, and edges with two equivalent Mg(3)O4 trigonal pyramids. The corner-sharing octahedral tilt angles are 10°. In the sixth Mg site, Mg(6) is bonded in a distorted T-shaped geometry to one O(9) and two equivalent O(4) atoms. In the seventh Mg site, Mg(7) is bonded to one O(8), two equivalent O(2), and two equivalent O(5) atoms to form MgO5 square pyramids that share  a cornercorner with one Mg(5)O6 octahedra, corners with two equivalent Mg(8)O6 octahedra, corners with two equivalent Mg(7)O5 square pyramids, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, and edges with four equivalent Mg(10)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-1°. In the eighth Mg site, Mg(8) is bonded to one O(7), one O(9), two equivalent O(3), and two equivalent O(5) atoms to form distorted MgO6 octahedra that share corners with two equivalent Mg(8)O6 octahedra, corners with two equivalent Mg(7)O5 square pyramids, corners with two equivalent Mg(1)O4 tetrahedra, edges with two equivalent Mg(4)O6 octahedra, and edges with four equivalent Mg(10)O5 square pyramids. The corner-sharing octahedral tilt angles are 45°. In the ninth Mg site, Mg(9) is bonded to one O(1), one O(10), one O(11), and two equivalent O(4) atoms to form MgO5 square pyramids that share  a cornercorner with one Mg(10)O5 square pyramid, corners with three equivalent Mg(9)O5 square pyramids,  a cornercorner with one Mg(1)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with two equivalent Mg(3)O4 trigonal pyramids. In the tenth Mg site, Mg(10) is bonded to one O(11), one O(2), one O(3), and two equivalent O(5) atoms to form MgO5 square pyramids that share  a cornercorner with one Mg(9)O5 square pyramid, corners with four equivalent Mg(10)O5 square pyramids,  an edgeedge with one Mg(2)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(8)O6 octahedra, and edges with two equivalent Mg(7)O5 square pyramids. B(1) is bonded in a 1-coordinate geometry to one O(3), two equivalent O(11), and two equivalent O(9) atoms. There are eleven inequivalent O sites. In the first O site, O(1) is bonded to one Mg(2), two equivalent Mg(5), and two equivalent Mg(9) atoms to form OMg5 square pyramids that share  a cornercorner with one O(2)CsMg5 octahedra, corners with two equivalent O(1)Mg5 square pyramids, corners with two equivalent O(6)Cs2Mg3 trigonal bipyramids, edges with two equivalent O(11)Mg5B octahedra, edges with two equivalent O(8)Mg6 octahedra, and edges with four equivalent O(4)Mg6 octahedra. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded to one Cs(1), one Mg(2), two equivalent Mg(10), and two equivalent Mg(7) atoms to form OCsMg5 octahedra that share corners with two equivalent O(2)CsMg5 octahedra,  a cornercorner with one O(1)Mg5 square pyramid, corners with two equivalent O(6)Cs2Mg3 trigonal bipyramids, corners with two equivalent O(3)Mg4B trigonal bipyramids, edges with two equivalent O(11)Mg5B octahedra, edges with two equivalent O(8)Mg6 octahedra, and edges with four equivalent O(5)Mg5 square pyramids. The corner-sharing octahedral tilt angles are 1°. In the third O site, O(3) is bonded to two equivalent Mg(10), two equivalent Mg(8), and one B(1) atom to form distorted OMg4B trigonal bipyramids that share corners with two equivalent O(2)CsMg5 octahedra, corners with two equivalent O(3)Mg4B trigonal bipyramids, edges with two equivalent O(9)Mg4B2 octahedra, edges with two equivalent O(11)Mg5B octahedra, and edges with four equivalent O(5)Mg5 square pyramids. The corner-sharing octahedral tilt angles are 7°. In the fourth O site, O(4) is bonded to one Mg(3), one Mg(4), one Mg(5), one Mg(6), and two equivalent Mg(9) atoms to form OMg6 octahedra that share corners with four equivalent O(4)Mg6 octahedra,  a cornercorner with one O(5)Mg5 square pyramid,  an edgeedge with one O(9)Mg4B2 octahedra,  an edgeedge with one O(8)Mg6 octahedra, edges with two equivalent O(11)Mg5B octahedra, edges with two equivalent O(1)Mg5 square pyramids, and  an edgeedge with one O(6)Cs2Mg3 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 4-25°. In the fifth O site, O(5) is bonded to one Mg(4), one Mg(7), one Mg(8), and two equivalent Mg(10) atoms to form OMg5 square pyramids that share  a cornercorner with one O(4)Mg6 octahedra, corners with four equivalent O(5)Mg5 square pyramids,  an edgeedge with one O(9)Mg4B2 octahedra,  an edgeedge with one O(8)Mg6 octahedra, edges with two equivalent O(2)CsMg5 octahedra, edges with two equivalent O(11)Mg5B octahedra, and edges with two equivalent O(3)Mg4B trigonal bipyramids. The corner-sharing octahedral tilt angles are 1°. In the sixth O site, O(6) is bonded to two equivalent Cs(1), one Mg(5), and two equivalent Mg(3) atoms to form OCs2Mg3 trigonal bipyramids that share  a cornercorner with one O(8)Mg6 octahedra, corners with two equivalent O(2)CsMg5 octahedra, corners with two equivalent O(1)Mg5 square pyramids, corners with two equivalent O(6)Cs2Mg3 trigonal bipyramids, and edges with two equivalent O(4)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-51°. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Mg(8) and two equivalent Mg(1) atoms. In the eighth O site, O(8) is bonded to one Mg(5), one Mg(7), two equivalent Mg(2), and two equivalent Mg(4) atoms to form OMg6 octahedra that share corners with two equivalent O(9)Mg4B2 octahedra, corners with two equivalent O(8)Mg6 octahedra,  a cornercorner with one O(6)Cs2Mg3 trigonal bipyramid, edges with two equivalent O(2)CsMg5 octahedra, edges with two equivalent O(4)Mg6 octahedra, edges with four equivalent O(11)Mg5B octahedra, edges with two equivalent O(1)Mg5 square pyramids, and edges with two equivalent O(5)Mg5 square pyramids. The corner-sharing octahedral tilt angles range from 2-3°. In the ninth O site, O(9) is bonded to one Mg(6), one Mg(8), two equivalent Mg(4), and two equivalent B(1) atoms to form OMg4B2 octahedra that share corners with two equivalent O(9)Mg4B2 octahedra, corners with two equivalent O(8)Mg6 octahedra, edges with two equivalent O(4)Mg6 octahedra, edges with four equivalent O(11)Mg5B octahedra, edges with two equivalent O(5)Mg5 square pyramids, and edges with two equivalent O(3)Mg4B trigonal bipyramids. The corner-sharing octahedral tilt angles range from 0-3°. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Cs(1), one Mg(1), one Mg(9), and two equivalent Mg(3) atoms. In the eleventh O site, O(11) is bonded to one Mg(10), one Mg(2), one Mg(9), two equivalent Mg(4), and one B(1) atom to form OMg5B octahedra that share corners with four equivalent O(11)Mg5B octahedra,  an edgeedge with one O(2)CsMg5 octahedra, edges with two equivalent O(9)Mg4B2 octahedra, edges with two equivalent O(4)Mg6 octahedra, edges with two equivalent O(8)Mg6 octahedra,  an edgeedge with one O(1)Mg5 square pyramid, edges with two equivalent O(5)Mg5 square pyramids, and  an edgeedge with one O(3)Mg4B trigonal bipyramid. The corner-sharing octahedral tilt angles range from 4-11°.
CsMg14BO15 crystallizes in the orthorhombic Pmm2 space group. Cs(1) is bonded in a 5-coordinate geometry to one O(2), two equivalent O(10), and two equivalent O(6) atoms. The Cs(1)-O(2) bond length is 2.83 Å. Both Cs(1)-O(10) bond lengths are 3.02 Å. Both Cs(1)-O(6) bond lengths are 2.64 Å. There are ten inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(10) and two equivalent O(7) atoms to form distorted MgO4 tetrahedra that share corners with two equivalent Mg(8)O6 octahedra, corners with two equivalent Mg(9)O5 square pyramids, corners with two equivalent Mg(1)O4 tetrahedra, and corners with four equivalent Mg(3)O4 trigonal pyramids. The corner-sharing octahedral tilt angles are 70°. Both Mg(1)-O(10) bond lengths are 1.98 Å. Both Mg(1)-O(7) bond lengths are 2.18 Å. In the second Mg site, Mg(2) is bonded to one O(1), one O(2), two equivalent O(11), and two equivalent O(8) atoms to form MgO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, edges with four equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(10)O5 square pyramids, edges with two equivalent Mg(7)O5 square pyramids, and edges with two equivalent Mg(9)O5 square pyramids. The corner-sharing octahedral tilt angles are 2°. The Mg(2)-O(1) bond length is 2.00 Å. The Mg(2)-O(2) bond length is 2.11 Å. Both Mg(2)-O(11) bond lengths are 2.07 Å. Both Mg(2)-O(8) bond lengths are 2.05 Å. In the third Mg site, Mg(3) is bonded to one O(4), one O(6), and two equivalent O(10) atoms to form distorted MgO4 trigonal pyramids that share  a cornercorner with one Mg(4)O6 octahedra, corners with two equivalent Mg(1)O4 tetrahedra, corners with three equivalent Mg(3)O4 trigonal pyramids,  an edgeedge with one Mg(5)O6 octahedra, and edges with two equivalent Mg(9)O5 square pyramids. The corner-sharing octahedral tilt angles are 8°. The Mg(3)-O(4) bond length is 2.12 Å. The Mg(3)-O(6) bond length is 2.06 Å. Both Mg(3)-O(10) bond lengths are 2.10 Å. In the fourth Mg site, Mg(4) is bonded to one O(4), one O(5), one O(8), one O(9), and two equivalent O(11) atoms to form MgO6 octahedra that share corners with four equivalent Mg(4)O6 octahedra,  a cornercorner with one Mg(3)O4 trigonal pyramid,  an edgeedge with one Mg(5)O6 octahedra,  an edgeedge with one Mg(8)O6 octahedra, edges with two equivalent Mg(2)O6 octahedra,  an edgeedge with one Mg(7)O5 square pyramid, edges with two equivalent Mg(10)O5 square pyramids, and edges with two equivalent Mg(9)O5 square pyramids. The corner-sharing octahedral tilt angles range from 4-10°. The Mg(4)-O(4) bond length is 2.21 Å. The Mg(4)-O(5) bond length is 2.22 Å. The Mg(4)-O(8) bond length is 2.14 Å. The Mg(4)-O(9) bond length is 2.07 Å. Both Mg(4)-O(11) bond lengths are 2.05 Å. In the fifth Mg site, Mg(5) is bonded to one O(6), one O(8), two equivalent O(1), and two equivalent O(4) atoms to form MgO6 octahedra that share corners with two equivalent Mg(5)O6 octahedra,  a cornercorner with one Mg(7)O5 square pyramid, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with four equivalent Mg(9)O5 square pyramids, and edges with two equivalent Mg(3)O4 trigonal pyramids. The corner-sharing octahedral tilt angles are 10°. The Mg(5)-O(6) bond length is 2.00 Å. The Mg(5)-O(8) bond length is 2.22 Å. Both Mg(5)-O(1) bond lengths are 2.06 Å. Both Mg(5)-O(4) bond lengths are 2.25 Å. In the sixth Mg site, Mg(6) is bonded in a distorted T-shaped geometry to one O(9) and two equivalent O(4) atoms. The Mg(6)-O(9) bond length is 1.95 Å. Both Mg(6)-O(4) bond lengths are 2.00 Å. In the seventh Mg site, Mg(7) is bonded to one O(8), two equivalent O(2), and two equivalent O(5) atoms to form MgO5 square pyramids that share  a cornercorner with one Mg(5)O6 octahedra, corners with two equivalent Mg(8)O6 octahedra, corners with two equivalent Mg(7)O5 square pyramids, edges with two equivalent Mg(2)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, and edges with four equivalent Mg(10)O5 square pyramids. The corner-sharing octahedral tilt angles range from 0-1°. The Mg(7)-O(8) bond length is 2.05 Å. Both Mg(7)-O(2) bond lengths are 2.05 Å. Both Mg(7)-O(5) bond lengths are 2.09 Å. In the eighth Mg site, Mg(8) is bonded to one O(7), one O(9), two equivalent O(3), and two equivalent O(5) atoms to form distorted MgO6 octahedra that share corners with two equivalent Mg(8)O6 octahedra, corners with two equivalent Mg(7)O5 square pyramids, corners with two equivalent Mg(1)O4 tetrahedra, edges with two equivalent Mg(4)O6 octahedra, and edges with four equivalent Mg(10)O5 square pyramids. The corner-sharing octahedral tilt angles are 45°. The Mg(8)-O(7) bond length is 2.23 Å. The Mg(8)-O(9) bond length is 2.33 Å. Both Mg(8)-O(3) bond lengths are 2.22 Å. Both Mg(8)-O(5) bond lengths are 2.14 Å. In the ninth Mg site, Mg(9) is bonded to one O(1), one O(10), one O(11), and two equivalent O(4) atoms to form MgO5 square pyramids that share  a cornercorner with one Mg(10)O5 square pyramid, corners with three equivalent Mg(9)O5 square pyramids,  a cornercorner with one Mg(1)O4 tetrahedra,  an edgeedge with one Mg(2)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with two equivalent Mg(3)O4 trigonal pyramids. The Mg(9)-O(1) bond length is 2.06 Å. The Mg(9)-O(10) bond length is 2.10 Å. The Mg(9)-O(11) bond length is 2.21 Å. Both Mg(9)-O(4) bond lengths are 2.06 Å. In the tenth Mg site, Mg(10) is bonded to one O(11), one O(2), one O(3), and two equivalent O(5) atoms to form MgO5 square pyramids that share  a cornercorner with one Mg(9)O5 square pyramid, corners with four equivalent Mg(10)O5 square pyramids,  an edgeedge with one Mg(2)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(8)O6 octahedra, and edges with two equivalent Mg(7)O5 square pyramids. The Mg(10)-O(11) bond length is 2.01 Å. The Mg(10)-O(2) bond length is 2.06 Å. The Mg(10)-O(3) bond length is 2.16 Å. Both Mg(10)-O(5) bond lengths are 2.07 Å. B(1) is bonded in a 1-coordinate geometry to one O(3), two equivalent O(11), and two equivalent O(9) atoms. The B(1)-O(3) bond length is 1.48 Å. Both B(1)-O(11) bond lengths are 2.14 Å. Both B(1)-O(9) bond lengths are 2.05 Å. There are eleven inequivalent O sites. In the first O site, O(1) is bonded to one Mg(2), two equivalent Mg(5), and two equivalent Mg(9) atoms to form OMg5 square pyramids that share  a cornercorner with one O(2)CsMg5 octahedra, corners with two equivalent O(1)Mg5 square pyramids, corners with two equivalent O(6)Cs2Mg3 trigonal bipyramids, edges with two equivalent O(11)Mg5B octahedra, edges with two equivalent O(8)Mg6 octahedra, and edges with four equivalent O(4)Mg6 octahedra. The corner-sharing octahedra are not tilted. In the second O site, O(2) is bonded to one Cs(1), one Mg(2), two equivalent Mg(10), and two equivalent Mg(7) atoms to form OCsMg5 octahedra that share corners with two equivalent O(2)CsMg5 octahedra,  a cornercorner with one O(1)Mg5 square pyramid, corners with two equivalent O(6)Cs2Mg3 trigonal bipyramids, corners with two equivalent O(3)Mg4B trigonal bipyramids, edges with two equivalent O(11)Mg5B octahedra, edges with two equivalent O(8)Mg6 octahedra, and edges with four equivalent O(5)Mg5 square pyramids. The corner-sharing octahedral tilt angles are 1°. In the third O site, O(3) is bonded to two equivalent Mg(10), two equivalent Mg(8), and one B(1) atom to form distorted OMg4B trigonal bipyramids that share corners with two equivalent O(2)CsMg5 octahedra, corners with two equivalent O(3)Mg4B trigonal bipyramids, edges with two equivalent O(9)Mg4B2 octahedra, edges with two equivalent O(11)Mg5B octahedra, and edges with four equivalent O(5)Mg5 square pyramids. The corner-sharing octahedral tilt angles are 7°. In the fourth O site, O(4) is bonded to one Mg(3), one Mg(4), one Mg(5), one Mg(6), and two equivalent Mg(9) atoms to form OMg6 octahedra that share corners with four equivalent O(4)Mg6 octahedra,  a cornercorner with one O(5)Mg5 square pyramid,  an edgeedge with one O(9)Mg4B2 octahedra,  an edgeedge with one O(8)Mg6 octahedra, edges with two equivalent O(11)Mg5B octahedra, edges with two equivalent O(1)Mg5 square pyramids, and  an edgeedge with one O(6)Cs2Mg3 trigonal bipyramid. The corner-sharing octahedral tilt angles range from 4-25°. In the fifth O site, O(5) is bonded to one Mg(4), one Mg(7), one Mg(8), and two equivalent Mg(10) atoms to form OMg5 square pyramids that share  a cornercorner with one O(4)Mg6 octahedra, corners with four equivalent O(5)Mg5 square pyramids,  an edgeedge with one O(9)Mg4B2 octahedra,  an edgeedge with one O(8)Mg6 octahedra, edges with two equivalent O(2)CsMg5 octahedra, edges with two equivalent O(11)Mg5B octahedra, and edges with two equivalent O(3)Mg4B trigonal bipyramids. The corner-sharing octahedral tilt angles are 1°. In the sixth O site, O(6) is bonded to two equivalent Cs(1), one Mg(5), and two equivalent Mg(3) atoms to form OCs2Mg3 trigonal bipyramids that share  a cornercorner with one O(8)Mg6 octahedra, corners with two equivalent O(2)CsMg5 octahedra, corners with two equivalent O(1)Mg5 square pyramids, corners with two equivalent O(6)Cs2Mg3 trigonal bipyramids, and edges with two equivalent O(4)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-51°. In the seventh O site, O(7) is bonded in a 3-coordinate geometry to one Mg(8) and two equivalent Mg(1) atoms. In the eighth O site, O(8) is bonded to one Mg(5), one Mg(7), two equivalent Mg(2), and two equivalent Mg(4) atoms to form OMg6 octahedra that share corners with two equivalent O(9)Mg4B2 octahedra, corners with two equivalent O(8)Mg6 octahedra,  a cornercorner with one O(6)Cs2Mg3 trigonal bipyramid, edges with two equivalent O(2)CsMg5 octahedra, edges with two equivalent O(4)Mg6 octahedra, edges with four equivalent O(11)Mg5B octahedra, edges with two equivalent O(1)Mg5 square pyramids, and edges with two equivalent O(5)Mg5 square pyramids. The corner-sharing octahedral tilt angles range from 2-3°. In the ninth O site, O(9) is bonded to one Mg(6), one Mg(8), two equivalent Mg(4), and two equivalent B(1) atoms to form OMg4B2 octahedra that share corners with two equivalent O(9)Mg4B2 octahedra, corners with two equivalent O(8)Mg6 octahedra, edges with two equivalent O(4)Mg6 octahedra, edges with four equivalent O(11)Mg5B octahedra, edges with two equivalent O(5)Mg5 square pyramids, and edges with two equivalent O(3)Mg4B trigonal bipyramids. The corner-sharing octahedral tilt angles range from 0-3°. In the tenth O site, O(10) is bonded in a 4-coordinate geometry to one Cs(1), one Mg(1), one Mg(9), and two equivalent Mg(3) atoms. In the eleventh O site, O(11) is bonded to one Mg(10), one Mg(2), one Mg(9), two equivalent Mg(4), and one B(1) atom to form OMg5B octahedra that share corners with four equivalent O(11)Mg5B octahedra,  an edgeedge with one O(2)CsMg5 octahedra, edges with two equivalent O(9)Mg4B2 octahedra, edges with two equivalent O(4)Mg6 octahedra, edges with two equivalent O(8)Mg6 octahedra,  an edgeedge with one O(1)Mg5 square pyramid, edges with two equivalent O(5)Mg5 square pyramids, and  an edgeedge with one O(3)Mg4B trigonal bipyramid. The corner-sharing octahedral tilt angles range from 4-11°.