Tc2Al2O5 crystallizes in the tetragonal P4/mmm space group. There are two inequivalent Tc sites. In the first Tc site, Tc(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. In the second Tc site, Tc(2) is bonded in a square co-planar geometry to four equivalent O(2) atoms. Al(1) is bonded to one O(2) and four equivalent O(1) atoms to form distorted corner-sharing AlO5 trigonal bipyramids. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Tc(1) and two equivalent Al(1) atoms to form distorted OAl2Tc2 tetrahedra that share corners with two equivalent O(2)Al2Tc4 octahedra, corners with ten equivalent O(1)Al2Tc2 tetrahedra, and edges with five equivalent O(1)Al2Tc2 tetrahedra. The corner-sharing octahedral tilt angles are 73°. In the second O site, O(2) is bonded to four equivalent Tc(2) and two equivalent Al(1) atoms to form distorted OAl2Tc4 octahedra that share corners with four equivalent O(2)Al2Tc4 octahedra, corners with eight equivalent O(1)Al2Tc2 tetrahedra, and edges with four equivalent O(2)Al2Tc4 octahedra. The corner-sharing octahedra are not tilted.
Tc2Al2O5 crystallizes in the tetragonal P4/mmm space group. There are two inequivalent Tc sites. In the first Tc site, Tc(1) is bonded in a body-centered cubic geometry to eight equivalent O(1) atoms. All Tc(1)-O(1) bond lengths are 2.21 Å. In the second Tc site, Tc(2) is bonded in a square co-planar geometry to four equivalent O(2) atoms. All Tc(2)-O(2) bond lengths are 2.53 Å. Al(1) is bonded to one O(2) and four equivalent O(1) atoms to form distorted corner-sharing AlO5 trigonal bipyramids. The Al(1)-O(2) bond length is 1.86 Å. All Al(1)-O(1) bond lengths are 1.87 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to two equivalent Tc(1) and two equivalent Al(1) atoms to form distorted OAl2Tc2 tetrahedra that share corners with two equivalent O(2)Al2Tc4 octahedra, corners with ten equivalent O(1)Al2Tc2 tetrahedra, and edges with five equivalent O(1)Al2Tc2 tetrahedra. The corner-sharing octahedral tilt angles are 73°. In the second O site, O(2) is bonded to four equivalent Tc(2) and two equivalent Al(1) atoms to form distorted OAl2Tc4 octahedra that share corners with four equivalent O(2)Al2Tc4 octahedra, corners with eight equivalent O(1)Al2Tc2 tetrahedra, and edges with four equivalent O(2)Al2Tc4 octahedra. The corner-sharing octahedra are not tilted.