PrTa7O19 crystallizes in the hexagonal P-6c2 space group. Pr(1) is bonded in a 8-coordinate geometry to two equivalent O(4) and six equivalent O(5) atoms. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and three equivalent O(2) atoms. In the second Ta site, Ta(2) is bonded in an octahedral geometry to six equivalent O(5) atoms. There are five inequivalent O sites. In the first O site, O(3) is bonded in a trigonal planar geometry to three equivalent Ta(1) atoms. In the second O site, O(4) is bonded to one Pr(1) and three equivalent Ta(1) atoms to form distorted corner-sharing OPrTa3 tetrahedra. In the third O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Pr(1), one Ta(1), and one Ta(2) atom. In the fourth O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Ta(1) atoms. In the fifth O site, O(2) is bonded in a distorted bent 150 degrees geometry to three equivalent Ta(1) atoms.
PrTa7O19 crystallizes in the hexagonal P-6c2 space group. Pr(1) is bonded in a 8-coordinate geometry to two equivalent O(4) and six equivalent O(5) atoms. Both Pr(1)-O(4) bond lengths are 2.64 Å. All Pr(1)-O(5) bond lengths are 2.46 Å. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded in a 7-coordinate geometry to one O(1), one O(3), one O(4), one O(5), and three equivalent O(2) atoms. The Ta(1)-O(1) bond length is 1.91 Å. The Ta(1)-O(3) bond length is 2.01 Å. The Ta(1)-O(4) bond length is 2.07 Å. The Ta(1)-O(5) bond length is 2.02 Å. There are a spread of Ta(1)-O(2) bond distances ranging from 1.98-2.47 Å. In the second Ta site, Ta(2) is bonded in an octahedral geometry to six equivalent O(5) atoms. All Ta(2)-O(5) bond lengths are 1.99 Å. There are five inequivalent O sites. In the first O site, O(3) is bonded in a trigonal planar geometry to three equivalent Ta(1) atoms. In the second O site, O(4) is bonded to one Pr(1) and three equivalent Ta(1) atoms to form distorted corner-sharing OPrTa3 tetrahedra. In the third O site, O(5) is bonded in a distorted trigonal non-coplanar geometry to one Pr(1), one Ta(1), and one Ta(2) atom. In the fourth O site, O(1) is bonded in a bent 150 degrees geometry to two equivalent Ta(1) atoms. In the fifth O site, O(2) is bonded in a distorted bent 150 degrees geometry to three equivalent Ta(1) atoms.