BaMg(BiO2)4 crystallizes in the trigonal P-31m space group. Ba(1) is bonded in a distorted hexagonal planar geometry to six equivalent O(1) atoms. Mg(1) is bonded to six equivalent O(1) atoms to form MgO6 octahedra that share corners with twelve equivalent Bi(1)O4 trigonal pyramids. Bi(1) is bonded to one O(2) and three equivalent O(1) atoms to form BiO4 trigonal pyramids that share corners with three equivalent Mg(1)O6 octahedra and corners with four equivalent Bi(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles are 58°. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), one Mg(1), and two equivalent Bi(1) atoms to form a mixture of distorted corner and edge-sharing OBaMgBi2 tetrahedra. In the second O site, O(2) is bonded in a linear geometry to two equivalent Bi(1) atoms.
BaMg(BiO2)4 crystallizes in the trigonal P-31m space group. Ba(1) is bonded in a distorted hexagonal planar geometry to six equivalent O(1) atoms. All Ba(1)-O(1) bond lengths are 2.88 Å. Mg(1) is bonded to six equivalent O(1) atoms to form MgO6 octahedra that share corners with twelve equivalent Bi(1)O4 trigonal pyramids. All Mg(1)-O(1) bond lengths are 2.24 Å. Bi(1) is bonded to one O(2) and three equivalent O(1) atoms to form BiO4 trigonal pyramids that share corners with three equivalent Mg(1)O6 octahedra and corners with four equivalent Bi(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles are 58°. The Bi(1)-O(2) bond length is 2.11 Å. All Bi(1)-O(1) bond lengths are 2.29 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), one Mg(1), and two equivalent Bi(1) atoms to form a mixture of distorted corner and edge-sharing OBaMgBi2 tetrahedra. In the second O site, O(2) is bonded in a linear geometry to two equivalent Bi(1) atoms.