KNaGdTaO5 crystallizes in the tetragonal P4/nmm space group. K(1) is bonded in a square co-planar geometry to four equivalent O(1) atoms. Na(1) is bonded to one O(1) and four equivalent O(2) atoms to form distorted NaO5 trigonal bipyramids that share corners with five equivalent Ta(1)O5 trigonal bipyramids. Gd(1) is bonded in a body-centered cubic geometry to eight equivalent O(2) atoms. Ta(1) is bonded to one O(1) and four equivalent O(2) atoms to form distorted TaO5 trigonal bipyramids that share corners with five equivalent Na(1)O5 trigonal bipyramids. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent K(1), one Na(1), and one Ta(1) atom to form distorted OK4NaTa octahedra that share corners with four equivalent O(1)K4NaTa octahedra, corners with eight equivalent O(2)NaGd2Ta tetrahedra, and edges with four equivalent O(1)K4NaTa octahedra. The corner-sharing octahedral tilt angles are 12°. In the second O site, O(2) is bonded to one Na(1), two equivalent Gd(1), and one Ta(1) atom to form distorted ONaGd2Ta tetrahedra that share corners with two equivalent O(1)K4NaTa octahedra, corners with ten equivalent O(2)NaGd2Ta tetrahedra, and edges with five equivalent O(2)NaGd2Ta tetrahedra. The corner-sharing octahedral tilt angles range from 71-72°.
KNaGdTaO5 crystallizes in the tetragonal P4/nmm space group. K(1) is bonded in a square co-planar geometry to four equivalent O(1) atoms. All K(1)-O(1) bond lengths are 2.85 Å. Na(1) is bonded to one O(1) and four equivalent O(2) atoms to form distorted NaO5 trigonal bipyramids that share corners with five equivalent Ta(1)O5 trigonal bipyramids. The Na(1)-O(1) bond length is 2.27 Å. All Na(1)-O(2) bond lengths are 2.27 Å. Gd(1) is bonded in a body-centered cubic geometry to eight equivalent O(2) atoms. All Gd(1)-O(2) bond lengths are 2.44 Å. Ta(1) is bonded to one O(1) and four equivalent O(2) atoms to form distorted TaO5 trigonal bipyramids that share corners with five equivalent Na(1)O5 trigonal bipyramids. The Ta(1)-O(1) bond length is 1.85 Å. All Ta(1)-O(2) bond lengths are 1.95 Å. There are two inequivalent O sites. In the first O site, O(1) is bonded to four equivalent K(1), one Na(1), and one Ta(1) atom to form distorted OK4NaTa octahedra that share corners with four equivalent O(1)K4NaTa octahedra, corners with eight equivalent O(2)NaGd2Ta tetrahedra, and edges with four equivalent O(1)K4NaTa octahedra. The corner-sharing octahedral tilt angles are 12°. In the second O site, O(2) is bonded to one Na(1), two equivalent Gd(1), and one Ta(1) atom to form distorted ONaGd2Ta tetrahedra that share corners with two equivalent O(1)K4NaTa octahedra, corners with ten equivalent O(2)NaGd2Ta tetrahedra, and edges with five equivalent O(2)NaGd2Ta tetrahedra. The corner-sharing octahedral tilt angles range from 71-72°.