Mg14FeNiO16 is alpha Po-derived structured and crystallizes in the orthorhombic Pmmm space group. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(6), and two equivalent O(9) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra; corners with two equivalent Mg(2)O6 octahedra; corners with two equivalent Fe(1)O6 octahedra; edges with four Mg(4,4)O6 octahedra; edges with four equivalent Mg(5)O6 octahedra; and edges with four equivalent Mg(7)O6 octahedra. The corner-sharing octahedra are not tilted. In the second Mg site, Mg(2) is bonded to two equivalent O(2), two equivalent O(7), and two equivalent O(9) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra; corners with two equivalent Mg(2)O6 octahedra; corners with two equivalent Ni(1)O6 octahedra; edges with four Mg(4,4)O6 octahedra; edges with four equivalent Mg(6)O6 octahedra; and edges with four equivalent Mg(7)O6 octahedra. The corner-sharing octahedra are not tilted. In the third Mg site, Mg(3) is bonded to one O(4), one O(5), two equivalent O(3), and two equivalent O(8) atoms to form MgO6 octahedra that share corners with two equivalent Mg(4)O6 octahedra, corners with four equivalent Mg(3)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, edges with two equivalent Mg(6)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with four equivalent Mg(7)O6 octahedra. The corner-sharing octahedra are not tilted. In the fourth Mg site, Mg(4) is bonded to one O(6), one O(7), two equivalent O(3), and two equivalent O(9) atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fifth Mg site, Mg(4) is bonded to one O(6), one O(7), two equivalent O(3), and two equivalent O(9) atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the sixth Mg site, Mg(5) is bonded to one O(4), one O(6), two equivalent O(1), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(6)O6 octahedra; corners with four equivalent Mg(5)O6 octahedra; edges with two equivalent Mg(1)O6 octahedra; edges with two equivalent Mg(3)O6 octahedra; edges with two Mg(4,4)O6 octahedra; edges with two equivalent Fe(1)O6 octahedra; and edges with four equivalent Mg(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the seventh Mg site, Mg(6) is bonded to one O(5), one O(7), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(5)O6 octahedra; corners with four equivalent Mg(6)O6 octahedra; edges with two equivalent Mg(2)O6 octahedra; edges with two equivalent Mg(3)O6 octahedra; edges with two Mg(4,4)O6 octahedra; edges with two equivalent Ni(1)O6 octahedra; and edges with four equivalent Mg(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the eighth Mg site, Mg(7) is bonded to one O(1), one O(2), one O(8), one O(9), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Mg(7)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with two equivalent Mg(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. Fe(1) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(8) atoms to form FeO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, edges with four equivalent Mg(3)O6 octahedra, edges with four equivalent Mg(5)O6 octahedra, and edges with four equivalent Mg(7)O6 octahedra. The corner-sharing octahedra are not tilted. Ni(1) is bonded to two equivalent O(2), two equivalent O(5), and two equivalent O(8) atoms to form NiO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, edges with four equivalent Mg(3)O6 octahedra, edges with four equivalent Mg(6)O6 octahedra, and edges with four equivalent Mg(7)O6 octahedra. The corner-sharing octahedra are not tilted. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), two equivalent Mg(5), two equivalent Mg(7), and one Fe(1) atom to form OMg5Fe octahedra that share corners with two equivalent O(2)Mg5Ni octahedra, corners with four equivalent O(1)Mg5Fe octahedra, edges with two equivalent O(4)Mg4Fe2 octahedra, edges with two equivalent O(8)Mg4FeNi octahedra, edges with two equivalent O(6)Mg6 octahedra, edges with two equivalent O(9)Mg6 octahedra, and edges with four equivalent O(3)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the second O site, O(2) is bonded to one Mg(2), two equivalent Mg(6), two equivalent Mg(7), and one Ni(1) atom to form OMg5Ni octahedra that share corners with two equivalent O(1)Mg5Fe octahedra, corners with four equivalent O(2)Mg5Ni octahedra, edges with two equivalent O(8)Mg4FeNi octahedra, edges with two equivalent O(5)Mg4Ni2 octahedra, edges with two equivalent O(7)Mg6 octahedra, edges with two equivalent O(9)Mg6 octahedra, and edges with four equivalent O(3)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the third O site, O(3) is bonded to one Mg(3), one Mg(4), one Mg(5), one Mg(6), and two equivalent Mg(7) atoms to form OMg6 octahedra that share corners with six equivalent O(3)Mg6 octahedra,  an edgeedge with one O(4)Mg4Fe2 octahedra,  an edgeedge with one O(5)Mg4Ni2 octahedra,  an edgeedge with one O(6)Mg6 octahedra,  an edgeedge with one O(7)Mg6 octahedra, edges with two equivalent O(8)Mg4FeNi octahedra, edges with two equivalent O(1)Mg5Fe octahedra, edges with two equivalent O(2)Mg5Ni octahedra, and edges with two equivalent O(9)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fourth O site, O(4) is bonded to two equivalent Mg(3), two equivalent Mg(5), and two equivalent Fe(1) atoms to form OMg4Fe2 octahedra that share corners with two equivalent O(4)Mg4Fe2 octahedra, corners with two equivalent O(5)Mg4Ni2 octahedra, corners with two equivalent O(6)Mg6 octahedra, edges with four equivalent O(8)Mg4FeNi octahedra, edges with four equivalent O(1)Mg5Fe octahedra, and edges with four equivalent O(3)Mg6 octahedra. The corner-sharing octahedra are not tilted. In the fifth O site, O(5) is bonded to two equivalent Mg(3), two equivalent Mg(6), and two equivalent Ni(1) atoms to form OMg4Ni2 octahedra that share corners with two equivalent O(4)Mg4Fe2 octahedra, corners with two equivalent O(5)Mg4Ni2 octahedra, corners with two equivalent O(7)Mg6 octahedra, edges with four equivalent O(8)Mg4FeNi octahedra, edges with four equivalent O(2)Mg5Ni octahedra, and edges with four equivalent O(3)Mg6 octahedra. The corner-sharing octahedra are not tilted. In the sixth O site, O(6) is bonded to two equivalent Mg(1); two Mg(4,4); and two equivalent Mg(5) atoms to form OMg6 octahedra that share corners with two equivalent O(4)Mg4Fe2 octahedra, corners with two equivalent O(6)Mg6 octahedra, corners with two equivalent O(7)Mg6 octahedra, edges with four equivalent O(1)Mg5Fe octahedra, edges with four equivalent O(3)Mg6 octahedra, and edges with four equivalent O(9)Mg6 octahedra. The corner-sharing octahedra are not tilted. In the seventh O site, O(7) is bonded to two equivalent Mg(2); two Mg(4,4); and two equivalent Mg(6) atoms to form OMg6 octahedra that share corners with two equivalent O(5)Mg4Ni2 octahedra, corners with two equivalent O(6)Mg6 octahedra, corners with two equivalent O(7)Mg6 octahedra, edges with four equivalent O(2)Mg5Ni octahedra, edges with four equivalent O(3)Mg6 octahedra, and edges with four equivalent O(9)Mg6 octahedra. The corner-sharing octahedra are not tilted. In the eighth O site, O(8) is bonded to two equivalent Mg(3), two equivalent Mg(7), one Fe(1), and one Ni(1) atom to form OMg4FeNi octahedra that share corners with two equivalent O(9)Mg6 octahedra, corners with four equivalent O(8)Mg4FeNi octahedra, edges with two equivalent O(4)Mg4Fe2 octahedra, edges with two equivalent O(5)Mg4Ni2 octahedra, edges with two equivalent O(1)Mg5Fe octahedra, edges with two equivalent O(2)Mg5Ni octahedra, and edges with four equivalent O(3)Mg6 octahedra. The corner-sharing octahedra are not tilted. In the ninth O site, O(9) is bonded to one Mg(1), one Mg(2), two equivalent Mg(4), and two equivalent Mg(7) atoms to form OMg6 octahedra that share corners with two equivalent O(8)Mg4FeNi octahedra, corners with four equivalent O(9)Mg6 octahedra, edges with two equivalent O(1)Mg5Fe octahedra, edges with two equivalent O(2)Mg5Ni octahedra, edges with two equivalent O(6)Mg6 octahedra, edges with two equivalent O(7)Mg6 octahedra, and edges with four equivalent O(3)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°.
Mg14FeNiO16 is alpha Po-derived structured and crystallizes in the orthorhombic Pmmm space group. There are eight inequivalent Mg sites. In the first Mg site, Mg(1) is bonded to two equivalent O(1), two equivalent O(6), and two equivalent O(9) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra; corners with two equivalent Mg(2)O6 octahedra; corners with two equivalent Fe(1)O6 octahedra; edges with four Mg(4,4)O6 octahedra; edges with four equivalent Mg(5)O6 octahedra; and edges with four equivalent Mg(7)O6 octahedra. The corner-sharing octahedra are not tilted. Both Mg(1)-O(1) bond lengths are 2.08 Å. Both Mg(1)-O(6) bond lengths are 2.14 Å. Both Mg(1)-O(9) bond lengths are 2.14 Å. In the second Mg site, Mg(2) is bonded to two equivalent O(2), two equivalent O(7), and two equivalent O(9) atoms to form MgO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra; corners with two equivalent Mg(2)O6 octahedra; corners with two equivalent Ni(1)O6 octahedra; edges with four Mg(4,4)O6 octahedra; edges with four equivalent Mg(6)O6 octahedra; and edges with four equivalent Mg(7)O6 octahedra. The corner-sharing octahedra are not tilted. Both Mg(2)-O(2) bond lengths are 2.13 Å. Both Mg(2)-O(7) bond lengths are 2.14 Å. Both Mg(2)-O(9) bond lengths are 2.12 Å. In the third Mg site, Mg(3) is bonded to one O(4), one O(5), two equivalent O(3), and two equivalent O(8) atoms to form MgO6 octahedra that share corners with two equivalent Mg(4)O6 octahedra, corners with four equivalent Mg(3)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, edges with two equivalent Mg(6)O6 octahedra, edges with two equivalent Fe(1)O6 octahedra, edges with two equivalent Ni(1)O6 octahedra, and edges with four equivalent Mg(7)O6 octahedra. The corner-sharing octahedra are not tilted. The Mg(3)-O(4) bond length is 2.14 Å. The Mg(3)-O(5) bond length is 2.11 Å. Both Mg(3)-O(3) bond lengths are 2.13 Å. Both Mg(3)-O(8) bond lengths are 2.14 Å. In the fourth Mg site, Mg(4) is bonded to one O(6), one O(7), two equivalent O(3), and two equivalent O(9) atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. The Mg(4)-O(6) bond length is 2.12 Å. The Mg(4)-O(7) bond length is 2.13 Å. Both Mg(4)-O(3) bond lengths are 2.14 Å. Both Mg(4)-O(9) bond lengths are 2.14 Å. In the fifth Mg site, Mg(4) is bonded to one O(6), one O(7), two equivalent O(3), and two equivalent O(9) atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. The Mg(4)-O(6) bond length is 2.12 Å. The Mg(4)-O(7) bond length is 2.13 Å. Both Mg(4)-O(3) bond lengths are 2.14 Å. Both Mg(4)-O(9) bond lengths are 2.14 Å. In the sixth Mg site, Mg(5) is bonded to one O(4), one O(6), two equivalent O(1), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(6)O6 octahedra; corners with four equivalent Mg(5)O6 octahedra; edges with two equivalent Mg(1)O6 octahedra; edges with two equivalent Mg(3)O6 octahedra; edges with two Mg(4,4)O6 octahedra; edges with two equivalent Fe(1)O6 octahedra; and edges with four equivalent Mg(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. The Mg(5)-O(4) bond length is 2.13 Å. The Mg(5)-O(6) bond length is 2.14 Å. Both Mg(5)-O(1) bond lengths are 2.14 Å. Both Mg(5)-O(3) bond lengths are 2.13 Å. In the seventh Mg site, Mg(6) is bonded to one O(5), one O(7), two equivalent O(2), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with two equivalent Mg(5)O6 octahedra; corners with four equivalent Mg(6)O6 octahedra; edges with two equivalent Mg(2)O6 octahedra; edges with two equivalent Mg(3)O6 octahedra; edges with two Mg(4,4)O6 octahedra; edges with two equivalent Ni(1)O6 octahedra; and edges with four equivalent Mg(7)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. The Mg(6)-O(5) bond length is 2.13 Å. The Mg(6)-O(7) bond length is 2.14 Å. Both Mg(6)-O(2) bond lengths are 2.14 Å. Both Mg(6)-O(3) bond lengths are 2.12 Å. In the eighth Mg site, Mg(7) is bonded to one O(1), one O(2), one O(8), one O(9), and two equivalent O(3) atoms to form MgO6 octahedra that share corners with six equivalent Mg(7)O6 octahedra,  an edgeedge with one Mg(1)O6 octahedra,  an edgeedge with one Mg(2)O6 octahedra,  an edgeedge with one Fe(1)O6 octahedra,  an edgeedge with one Ni(1)O6 octahedra, edges with two equivalent Mg(3)O6 octahedra, edges with two equivalent Mg(4)O6 octahedra, edges with two equivalent Mg(5)O6 octahedra, and edges with two equivalent Mg(6)O6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. The Mg(7)-O(1) bond length is 2.13 Å. The Mg(7)-O(2) bond length is 2.12 Å. The Mg(7)-O(8) bond length is 2.14 Å. The Mg(7)-O(9) bond length is 2.13 Å. Both Mg(7)-O(3) bond lengths are 2.14 Å. Fe(1) is bonded to two equivalent O(1), two equivalent O(4), and two equivalent O(8) atoms to form FeO6 octahedra that share corners with two equivalent Mg(1)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, edges with four equivalent Mg(3)O6 octahedra, edges with four equivalent Mg(5)O6 octahedra, and edges with four equivalent Mg(7)O6 octahedra. The corner-sharing octahedra are not tilted. Both Fe(1)-O(1) bond lengths are 2.19 Å. Both Fe(1)-O(4) bond lengths are 2.14 Å. Both Fe(1)-O(8) bond lengths are 2.14 Å. Ni(1) is bonded to two equivalent O(2), two equivalent O(5), and two equivalent O(8) atoms to form NiO6 octahedra that share corners with two equivalent Mg(2)O6 octahedra, corners with two equivalent Fe(1)O6 octahedra, corners with two equivalent Ni(1)O6 octahedra, edges with four equivalent Mg(3)O6 octahedra, edges with four equivalent Mg(6)O6 octahedra, and edges with four equivalent Mg(7)O6 octahedra. The corner-sharing octahedra are not tilted. Both Ni(1)-O(2) bond lengths are 2.14 Å. Both Ni(1)-O(5) bond lengths are 2.14 Å. Both Ni(1)-O(8) bond lengths are 2.11 Å. There are nine inequivalent O sites. In the first O site, O(1) is bonded to one Mg(1), two equivalent Mg(5), two equivalent Mg(7), and one Fe(1) atom to form OMg5Fe octahedra that share corners with two equivalent O(2)Mg5Ni octahedra, corners with four equivalent O(1)Mg5Fe octahedra, edges with two equivalent O(4)Mg4Fe2 octahedra, edges with two equivalent O(8)Mg4FeNi octahedra, edges with two equivalent O(6)Mg6 octahedra, edges with two equivalent O(9)Mg6 octahedra, and edges with four equivalent O(3)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-3°. In the second O site, O(2) is bonded to one Mg(2), two equivalent Mg(6), two equivalent Mg(7), and one Ni(1) atom to form OMg5Ni octahedra that share corners with two equivalent O(1)Mg5Fe octahedra, corners with four equivalent O(2)Mg5Ni octahedra, edges with two equivalent O(8)Mg4FeNi octahedra, edges with two equivalent O(5)Mg4Ni2 octahedra, edges with two equivalent O(7)Mg6 octahedra, edges with two equivalent O(9)Mg6 octahedra, and edges with four equivalent O(3)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the third O site, O(3) is bonded to one Mg(3), one Mg(4), one Mg(5), one Mg(6), and two equivalent Mg(7) atoms to form OMg6 octahedra that share corners with six equivalent O(3)Mg6 octahedra,  an edgeedge with one O(4)Mg4Fe2 octahedra,  an edgeedge with one O(5)Mg4Ni2 octahedra,  an edgeedge with one O(6)Mg6 octahedra,  an edgeedge with one O(7)Mg6 octahedra, edges with two equivalent O(8)Mg4FeNi octahedra, edges with two equivalent O(1)Mg5Fe octahedra, edges with two equivalent O(2)Mg5Ni octahedra, and edges with two equivalent O(9)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°. In the fourth O site, O(4) is bonded to two equivalent Mg(3), two equivalent Mg(5), and two equivalent Fe(1) atoms to form OMg4Fe2 octahedra that share corners with two equivalent O(4)Mg4Fe2 octahedra, corners with two equivalent O(5)Mg4Ni2 octahedra, corners with two equivalent O(6)Mg6 octahedra, edges with four equivalent O(8)Mg4FeNi octahedra, edges with four equivalent O(1)Mg5Fe octahedra, and edges with four equivalent O(3)Mg6 octahedra. The corner-sharing octahedra are not tilted. In the fifth O site, O(5) is bonded to two equivalent Mg(3), two equivalent Mg(6), and two equivalent Ni(1) atoms to form OMg4Ni2 octahedra that share corners with two equivalent O(4)Mg4Fe2 octahedra, corners with two equivalent O(5)Mg4Ni2 octahedra, corners with two equivalent O(7)Mg6 octahedra, edges with four equivalent O(8)Mg4FeNi octahedra, edges with four equivalent O(2)Mg5Ni octahedra, and edges with four equivalent O(3)Mg6 octahedra. The corner-sharing octahedra are not tilted. In the sixth O site, O(6) is bonded to two equivalent Mg(1); two Mg(4,4); and two equivalent Mg(5) atoms to form OMg6 octahedra that share corners with two equivalent O(4)Mg4Fe2 octahedra, corners with two equivalent O(6)Mg6 octahedra, corners with two equivalent O(7)Mg6 octahedra, edges with four equivalent O(1)Mg5Fe octahedra, edges with four equivalent O(3)Mg6 octahedra, and edges with four equivalent O(9)Mg6 octahedra. The corner-sharing octahedra are not tilted. In the seventh O site, O(7) is bonded to two equivalent Mg(2); two Mg(4,4); and two equivalent Mg(6) atoms to form OMg6 octahedra that share corners with two equivalent O(5)Mg4Ni2 octahedra, corners with two equivalent O(6)Mg6 octahedra, corners with two equivalent O(7)Mg6 octahedra, edges with four equivalent O(2)Mg5Ni octahedra, edges with four equivalent O(3)Mg6 octahedra, and edges with four equivalent O(9)Mg6 octahedra. The corner-sharing octahedra are not tilted. In the eighth O site, O(8) is bonded to two equivalent Mg(3), two equivalent Mg(7), one Fe(1), and one Ni(1) atom to form OMg4FeNi octahedra that share corners with two equivalent O(9)Mg6 octahedra, corners with four equivalent O(8)Mg4FeNi octahedra, edges with two equivalent O(4)Mg4Fe2 octahedra, edges with two equivalent O(5)Mg4Ni2 octahedra, edges with two equivalent O(1)Mg5Fe octahedra, edges with two equivalent O(2)Mg5Ni octahedra, and edges with four equivalent O(3)Mg6 octahedra. The corner-sharing octahedra are not tilted. In the ninth O site, O(9) is bonded to one Mg(1), one Mg(2), two equivalent Mg(4), and two equivalent Mg(7) atoms to form OMg6 octahedra that share corners with two equivalent O(8)Mg4FeNi octahedra, corners with four equivalent O(9)Mg6 octahedra, edges with two equivalent O(1)Mg5Fe octahedra, edges with two equivalent O(2)Mg5Ni octahedra, edges with two equivalent O(6)Mg6 octahedra, edges with two equivalent O(7)Mg6 octahedra, and edges with four equivalent O(3)Mg6 octahedra. The corner-sharing octahedral tilt angles range from 0-1°.