Ba2Tc2O5 crystallizes in the tetragonal P4/mmm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to eight equivalent O(1) atoms to form distorted BaO8 hexagonal bipyramids that share corners with eight equivalent Ba(2)O12 cuboctahedra, edges with four equivalent Ba(1)O8 hexagonal bipyramids, edges with eight equivalent Tc(1)O5 square pyramids, and faces with two equivalent Ba(2)O12 cuboctahedra. In the second Ba site, Ba(2) is bonded to four equivalent O(2) and eight equivalent O(1) atoms to form BaO12 cuboctahedra that share corners with four equivalent Ba(2)O12 cuboctahedra, corners with eight equivalent Ba(1)O8 hexagonal bipyramids, faces with four equivalent Ba(2)O12 cuboctahedra, faces with two equivalent Ba(1)O8 hexagonal bipyramids, and faces with eight equivalent Tc(1)O5 square pyramids. Tc(1) is bonded to one O(2) and four equivalent O(1) atoms to form TcO5 square pyramids that share corners with five equivalent Tc(1)O5 square pyramids, edges with four equivalent Ba(1)O8 hexagonal bipyramids, and faces with four equivalent Ba(2)O12 cuboctahedra. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Tc(1) atoms to form a mixture of distorted face, corner, and edge-sharing OBa4Tc2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the second O site, O(2) is bonded to four equivalent Ba(2) and two equivalent Tc(1) atoms to form a mixture of face, corner, and edge-sharing OBa4Tc2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°.
Ba2Tc2O5 crystallizes in the tetragonal P4/mmm space group. There are two inequivalent Ba sites. In the first Ba site, Ba(1) is bonded to eight equivalent O(1) atoms to form distorted BaO8 hexagonal bipyramids that share corners with eight equivalent Ba(2)O12 cuboctahedra, edges with four equivalent Ba(1)O8 hexagonal bipyramids, edges with eight equivalent Tc(1)O5 square pyramids, and faces with two equivalent Ba(2)O12 cuboctahedra. All Ba(1)-O(1) bond lengths are 2.83 Å. In the second Ba site, Ba(2) is bonded to four equivalent O(2) and eight equivalent O(1) atoms to form BaO12 cuboctahedra that share corners with four equivalent Ba(2)O12 cuboctahedra, corners with eight equivalent Ba(1)O8 hexagonal bipyramids, faces with four equivalent Ba(2)O12 cuboctahedra, faces with two equivalent Ba(1)O8 hexagonal bipyramids, and faces with eight equivalent Tc(1)O5 square pyramids. All Ba(2)-O(2) bond lengths are 2.81 Å. All Ba(2)-O(1) bond lengths are 3.00 Å. Tc(1) is bonded to one O(2) and four equivalent O(1) atoms to form TcO5 square pyramids that share corners with five equivalent Tc(1)O5 square pyramids, edges with four equivalent Ba(1)O8 hexagonal bipyramids, and faces with four equivalent Ba(2)O12 cuboctahedra. The Tc(1)-O(2) bond length is 2.21 Å. All Tc(1)-O(1) bond lengths are 1.99 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Ba(1), two equivalent Ba(2), and two equivalent Tc(1) atoms to form a mixture of distorted face, corner, and edge-sharing OBa4Tc2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°. In the second O site, O(2) is bonded to four equivalent Ba(2) and two equivalent Tc(1) atoms to form a mixture of face, corner, and edge-sharing OBa4Tc2 octahedra. The corner-sharing octahedral tilt angles range from 0-62°.