RbTaO3 is Pb(Zr_(1-x)Ti_x)O3-like structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 8-coordinate geometry to one O(1), one O(3), two equivalent O(4), and four equivalent O(2) atoms. In the second Rb site, Rb(2) is bonded in a 4-coordinate geometry to two equivalent O(3) and two equivalent O(4) atoms. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form a mixture of corner and edge-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles are 4°. In the second Ta site, Ta(2) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form a mixture of distorted corner and edge-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Rb(1), one Ta(2), and two equivalent Ta(1) atoms to form edge-sharing ORbTa3 trigonal pyramids. In the second O site, O(2) is bonded in a linear geometry to two equivalent Rb(1), one Ta(1), and one Ta(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Rb(1), two equivalent Rb(2), and one Ta(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Rb(1), one Rb(2), one Ta(1), and one Ta(2) atom.
RbTaO3 is Pb(Zr_(1-x)Ti_x)O3-like structured and crystallizes in the monoclinic C2/m space group. There are two inequivalent Rb sites. In the first Rb site, Rb(1) is bonded in a 8-coordinate geometry to one O(1), one O(3), two equivalent O(4), and four equivalent O(2) atoms. The Rb(1)-O(1) bond length is 2.68 Å. The Rb(1)-O(3) bond length is 2.86 Å. Both Rb(1)-O(4) bond lengths are 2.87 Å. There are two shorter (3.10 Å) and two longer (3.11 Å) Rb(1)-O(2) bond lengths. In the second Rb site, Rb(2) is bonded in a 4-coordinate geometry to two equivalent O(3) and two equivalent O(4) atoms. Both Rb(2)-O(3) bond lengths are 2.85 Å. Both Rb(2)-O(4) bond lengths are 2.77 Å. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms to form a mixture of corner and edge-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles are 4°. Both Ta(1)-O(1) bond lengths are 2.07 Å. Both Ta(1)-O(2) bond lengths are 1.93 Å. Both Ta(1)-O(4) bond lengths are 2.00 Å. In the second Ta site, Ta(2) is bonded to one O(1), one O(3), two equivalent O(2), and two equivalent O(4) atoms to form a mixture of distorted corner and edge-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles are 4°. The Ta(2)-O(1) bond length is 2.32 Å. The Ta(2)-O(3) bond length is 1.82 Å. Both Ta(2)-O(2) bond lengths are 2.02 Å. Both Ta(2)-O(4) bond lengths are 1.98 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded to one Rb(1), one Ta(2), and two equivalent Ta(1) atoms to form edge-sharing ORbTa3 trigonal pyramids. In the second O site, O(2) is bonded in a linear geometry to two equivalent Rb(1), one Ta(1), and one Ta(2) atom. In the third O site, O(3) is bonded in a distorted single-bond geometry to one Rb(1), two equivalent Rb(2), and one Ta(2) atom. In the fourth O site, O(4) is bonded in a 4-coordinate geometry to one Rb(1), one Rb(2), one Ta(1), and one Ta(2) atom.