CsTa2P5O18 crystallizes in the triclinic P-1 space group. Cs(1) is bonded in a 8-coordinate geometry to one O(6), one O(9), two equivalent O(2), two equivalent O(3), and two equivalent O(7) atoms. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(10), one O(11), one O(18), one O(4), and one O(8) atom to form TaO6 octahedra that share  a cornercorner with one P(5)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and corners with three equivalent P(3)O4 tetrahedra. In the second Ta site, Ta(2) is bonded to one O(13), one O(14), one O(15), one O(17), one O(5), and one O(6) atom to form TaO6 octahedra that share  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and corners with three equivalent P(1)O4 tetrahedra. There are five inequivalent P sites. In the first P site, P(1) is bonded to one O(13), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Ta(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 22-38°. In the second P site, P(2) is bonded to one O(10), one O(16), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with two equivalent Ta(1)O6 octahedra and  a cornercorner with one P(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 17-18°. In the third P site, P(3) is bonded to one O(1), one O(11), one O(17), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Ta(2)O6 octahedra and corners with three equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-30°. In the fourth P site, P(4) is bonded to one O(12), one O(14), one O(15), and one O(2) atom to form PO4 tetrahedra that share corners with two equivalent Ta(2)O6 octahedra and  a cornercorner with one P(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 9-28°. In the fifth P site, P(5) is bonded to one O(12), one O(16), one O(18), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 22°. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Ta(1) and one P(3) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Cs(1) and one P(4) atom. In the third O site, O(3) is bonded in a single-bond geometry to two equivalent Cs(1) and one P(2) atom. In the fourth O site, O(4) is bonded in a linear geometry to one Ta(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Ta(2) and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Cs(1), one Ta(2), and one P(1) atom. In the seventh O site, O(7) is bonded in a single-bond geometry to two equivalent Cs(1) and one P(1) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Ta(1) and one P(3) atom. In the ninth O site, O(9) is bonded in a single-bond geometry to one Cs(1) and one P(5) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Ta(1) and one P(2) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one Ta(1) and one P(3) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to one P(4) and one P(5) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Ta(2) and one P(1) atom. In the fourteenth O site, O(14) is bonded in a linear geometry to one Ta(2) and one P(4) atom. In the fifteenth O site, O(15) is bonded in a bent 150 degrees geometry to one Ta(2) and one P(4) atom. In the sixteenth O site, O(16) is bonded in a bent 120 degrees geometry to one P(2) and one P(5) atom. In the seventeenth O site, O(17) is bonded in a linear geometry to one Ta(2) and one P(3) atom. In the eighteenth O site, O(18) is bonded in a bent 150 degrees geometry to one Ta(1) and one P(5) atom.
CsTa2P5O18 crystallizes in the triclinic P-1 space group. Cs(1) is bonded in a 8-coordinate geometry to one O(6), one O(9), two equivalent O(2), two equivalent O(3), and two equivalent O(7) atoms. The Cs(1)-O(6) bond length is 3.53 Å. The Cs(1)-O(9) bond length is 3.23 Å. There is one shorter (3.12 Å) and one longer (3.29 Å) Cs(1)-O(2) bond length. There is one shorter (3.22 Å) and one longer (3.35 Å) Cs(1)-O(3) bond length. There is one shorter (3.12 Å) and one longer (3.14 Å) Cs(1)-O(7) bond length. There are two inequivalent Ta sites. In the first Ta site, Ta(1) is bonded to one O(1), one O(10), one O(11), one O(18), one O(4), and one O(8) atom to form TaO6 octahedra that share  a cornercorner with one P(5)O4 tetrahedra, corners with two equivalent P(2)O4 tetrahedra, and corners with three equivalent P(3)O4 tetrahedra. The Ta(1)-O(1) bond length is 1.98 Å. The Ta(1)-O(10) bond length is 1.93 Å. The Ta(1)-O(11) bond length is 1.98 Å. The Ta(1)-O(18) bond length is 1.95 Å. The Ta(1)-O(4) bond length is 1.92 Å. The Ta(1)-O(8) bond length is 2.00 Å. In the second Ta site, Ta(2) is bonded to one O(13), one O(14), one O(15), one O(17), one O(5), and one O(6) atom to form TaO6 octahedra that share  a cornercorner with one P(3)O4 tetrahedra, corners with two equivalent P(4)O4 tetrahedra, and corners with three equivalent P(1)O4 tetrahedra. The Ta(2)-O(13) bond length is 1.92 Å. The Ta(2)-O(14) bond length is 1.96 Å. The Ta(2)-O(15) bond length is 1.98 Å. The Ta(2)-O(17) bond length is 2.01 Å. The Ta(2)-O(5) bond length is 1.94 Å. The Ta(2)-O(6) bond length is 1.97 Å. There are five inequivalent P sites. In the first P site, P(1) is bonded to one O(13), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share corners with three equivalent Ta(2)O6 octahedra. The corner-sharing octahedral tilt angles range from 22-38°. The P(1)-O(13) bond length is 1.57 Å. The P(1)-O(5) bond length is 1.56 Å. The P(1)-O(6) bond length is 1.55 Å. The P(1)-O(7) bond length is 1.46 Å. In the second P site, P(2) is bonded to one O(10), one O(16), one O(3), and one O(4) atom to form PO4 tetrahedra that share corners with two equivalent Ta(1)O6 octahedra and  a cornercorner with one P(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 17-18°. The P(2)-O(10) bond length is 1.56 Å. The P(2)-O(16) bond length is 1.60 Å. The P(2)-O(3) bond length is 1.45 Å. The P(2)-O(4) bond length is 1.55 Å. In the third P site, P(3) is bonded to one O(1), one O(11), one O(17), and one O(8) atom to form PO4 tetrahedra that share  a cornercorner with one Ta(2)O6 octahedra and corners with three equivalent Ta(1)O6 octahedra. The corner-sharing octahedral tilt angles range from 7-30°. The P(3)-O(1) bond length is 1.53 Å. The P(3)-O(11) bond length is 1.53 Å. The P(3)-O(17) bond length is 1.51 Å. The P(3)-O(8) bond length is 1.52 Å. In the fourth P site, P(4) is bonded to one O(12), one O(14), one O(15), and one O(2) atom to form PO4 tetrahedra that share corners with two equivalent Ta(2)O6 octahedra and  a cornercorner with one P(5)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 9-28°. The P(4)-O(12) bond length is 1.62 Å. The P(4)-O(14) bond length is 1.54 Å. The P(4)-O(15) bond length is 1.54 Å. The P(4)-O(2) bond length is 1.46 Å. In the fifth P site, P(5) is bonded to one O(12), one O(16), one O(18), and one O(9) atom to form PO4 tetrahedra that share  a cornercorner with one Ta(1)O6 octahedra,  a cornercorner with one P(2)O4 tetrahedra, and  a cornercorner with one P(4)O4 tetrahedra. The corner-sharing octahedral tilt angles are 22°. The P(5)-O(12) bond length is 1.57 Å. The P(5)-O(16) bond length is 1.59 Å. The P(5)-O(18) bond length is 1.54 Å. The P(5)-O(9) bond length is 1.46 Å. There are eighteen inequivalent O sites. In the first O site, O(1) is bonded in a bent 150 degrees geometry to one Ta(1) and one P(3) atom. In the second O site, O(2) is bonded in a distorted single-bond geometry to two equivalent Cs(1) and one P(4) atom. In the third O site, O(3) is bonded in a single-bond geometry to two equivalent Cs(1) and one P(2) atom. In the fourth O site, O(4) is bonded in a linear geometry to one Ta(1) and one P(2) atom. In the fifth O site, O(5) is bonded in a bent 150 degrees geometry to one Ta(2) and one P(1) atom. In the sixth O site, O(6) is bonded in a distorted bent 150 degrees geometry to one Cs(1), one Ta(2), and one P(1) atom. In the seventh O site, O(7) is bonded in a single-bond geometry to two equivalent Cs(1) and one P(1) atom. In the eighth O site, O(8) is bonded in a bent 150 degrees geometry to one Ta(1) and one P(3) atom. In the ninth O site, O(9) is bonded in a single-bond geometry to one Cs(1) and one P(5) atom. In the tenth O site, O(10) is bonded in a bent 150 degrees geometry to one Ta(1) and one P(2) atom. In the eleventh O site, O(11) is bonded in a bent 150 degrees geometry to one Ta(1) and one P(3) atom. In the twelfth O site, O(12) is bonded in a bent 120 degrees geometry to one P(4) and one P(5) atom. In the thirteenth O site, O(13) is bonded in a bent 150 degrees geometry to one Ta(2) and one P(1) atom. In the fourteenth O site, O(14) is bonded in a linear geometry to one Ta(2) and one P(4) atom. In the fifteenth O site, O(15) is bonded in a bent 150 degrees geometry to one Ta(2) and one P(4) atom. In the sixteenth O site, O(16) is bonded in a bent 120 degrees geometry to one P(2) and one P(5) atom. In the seventeenth O site, O(17) is bonded in a linear geometry to one Ta(2) and one P(3) atom. In the eighteenth O site, O(18) is bonded in a bent 150 degrees geometry to one Ta(1) and one P(5) atom.