BaCa(SbO2)4 crystallizes in the trigonal P-31m space group. Ba(1) is bonded in a 6-coordinate geometry to six equivalent O(1) atoms. Ca(1) is bonded to six equivalent O(1) atoms to form CaO6 octahedra that share corners with twelve equivalent Sb(1)O4 trigonal pyramids. Sb(1) is bonded to one O(2) and three equivalent O(1) atoms to form SbO4 trigonal pyramids that share corners with three equivalent Ca(1)O6 octahedra and corners with four equivalent Sb(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles are 63°. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), one Ca(1), and two equivalent Sb(1) atoms to form a mixture of corner and edge-sharing OBaCaSb2 tetrahedra. In the second O site, O(2) is bonded in a linear geometry to two equivalent Sb(1) atoms.
BaCa(SbO2)4 crystallizes in the trigonal P-31m space group. Ba(1) is bonded in a 6-coordinate geometry to six equivalent O(1) atoms. All Ba(1)-O(1) bond lengths are 2.79 Å. Ca(1) is bonded to six equivalent O(1) atoms to form CaO6 octahedra that share corners with twelve equivalent Sb(1)O4 trigonal pyramids. All Ca(1)-O(1) bond lengths are 2.48 Å. Sb(1) is bonded to one O(2) and three equivalent O(1) atoms to form SbO4 trigonal pyramids that share corners with three equivalent Ca(1)O6 octahedra and corners with four equivalent Sb(1)O4 trigonal pyramids. The corner-sharing octahedral tilt angles are 63°. The Sb(1)-O(2) bond length is 2.01 Å. All Sb(1)-O(1) bond lengths are 2.20 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to one Ba(1), one Ca(1), and two equivalent Sb(1) atoms to form a mixture of corner and edge-sharing OBaCaSb2 tetrahedra. In the second O site, O(2) is bonded in a linear geometry to two equivalent Sb(1) atoms.