BaTb2Mn2O7 crystallizes in the tetragonal I4/mmm space group. Ba(1) is bonded to four equivalent O(3) and eight equivalent O(1) atoms to form BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ba(1)O12 cuboctahedra, and faces with eight equivalent Mn(1)O6 octahedra. Tb(1) is bonded in a 9-coordinate geometry to four equivalent O(1) and five equivalent O(2) atoms. Mn(1) is bonded to one O(2), one O(3), and four equivalent O(1) atoms to form MnO6 octahedra that share corners with five equivalent Mn(1)O6 octahedra and faces with four equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-11°. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Tb(1), and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded in a distorted linear geometry to five equivalent Tb(1) and one Mn(1) atom. In the third O site, O(3) is bonded to four equivalent Ba(1) and two equivalent Mn(1) atoms to form a mixture of corner and edge-sharing OBa4Mn2 octahedra. The corner-sharing octahedra are not tilted.
BaTb2Mn2O7 crystallizes in the tetragonal I4/mmm space group. Ba(1) is bonded to four equivalent O(3) and eight equivalent O(1) atoms to form BaO12 cuboctahedra that share corners with four equivalent Ba(1)O12 cuboctahedra, faces with four equivalent Ba(1)O12 cuboctahedra, and faces with eight equivalent Mn(1)O6 octahedra. All Ba(1)-O(3) bond lengths are 2.79 Å. All Ba(1)-O(1) bond lengths are 2.99 Å. Tb(1) is bonded in a 9-coordinate geometry to four equivalent O(1) and five equivalent O(2) atoms. All Tb(1)-O(1) bond lengths are 2.43 Å. There is one shorter (2.17 Å) and four longer (2.84 Å) Tb(1)-O(2) bond lengths. Mn(1) is bonded to one O(2), one O(3), and four equivalent O(1) atoms to form MnO6 octahedra that share corners with five equivalent Mn(1)O6 octahedra and faces with four equivalent Ba(1)O12 cuboctahedra. The corner-sharing octahedral tilt angles range from 0-11°. The Mn(1)-O(2) bond length is 2.14 Å. The Mn(1)-O(3) bond length is 2.07 Å. All Mn(1)-O(1) bond lengths are 1.98 Å. There are three inequivalent O sites. In the first O site, O(1) is bonded in a 6-coordinate geometry to two equivalent Ba(1), two equivalent Tb(1), and two equivalent Mn(1) atoms. In the second O site, O(2) is bonded in a distorted linear geometry to five equivalent Tb(1) and one Mn(1) atom. In the third O site, O(3) is bonded to four equivalent Ba(1) and two equivalent Mn(1) atoms to form a mixture of corner and edge-sharing OBa4Mn2 octahedra. The corner-sharing octahedra are not tilted.