K4P6O19NiO6 crystallizes in the orthorhombic Fmm2 space group. The structure consists of four NiO6 clusters inside a K4P6O19 framework. In each NiO6 cluster, Ni(1) is bonded in an octahedral geometry to two equivalent O(7), two equivalent O(8), and two equivalent O(9) atoms. There are three inequivalent O sites. In the first O site, O(9) is bonded in a single-bond geometry to one Ni(1) atom. In the second O site, O(8) is bonded in a single-bond geometry to one Ni(1) atom. In the third O site, O(7) is bonded in a single-bond geometry to one Ni(1) atom. In the K4P6O19 framework, there are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), two equivalent O(4), and two equivalent O(6) atoms. In the second K site, K(2) is bonded to one O(10), one O(3), two equivalent O(5), and two equivalent O(6) atoms to form KO6 octahedra that share  a cornercorner with one K(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with four equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 46°. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(3), one O(4), and two equivalent O(1) atoms to form PO4 tetrahedra that share  a cornercorner with one K(2)O6 octahedra and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 38°. In the second P site, P(2) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent K(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-62°. There are seven inequivalent O sites. In the first O site, O(10) is bonded in a distorted bent 120 degrees geometry to two equivalent K(2) atoms. In the second O site, O(1) is bonded in a bent 120 degrees geometry to one K(1), one P(1), and one P(2) atom. In the third O site, O(2) is bonded in a distorted bent 120 degrees geometry to two equivalent P(2) atoms. In the fourth O site, O(3) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one P(1) atom. In the fifth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent K(1) and one P(1) atom. In the sixth O site, O(5) is bonded in a distorted single-bond geometry to one K(2) and one P(2) atom. In the seventh O site, O(6) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one P(2) atom.
K4P6O19NiO6 crystallizes in the orthorhombic Fmm2 space group. The structure consists of four NiO6 clusters inside a K4P6O19 framework. In each NiO6 cluster, Ni(1) is bonded in an octahedral geometry to two equivalent O(7), two equivalent O(8), and two equivalent O(9) atoms. Both Ni(1)-O(7) bond lengths are 1.97 Å. Both Ni(1)-O(8) bond lengths are 1.83 Å. Both Ni(1)-O(9) bond lengths are 1.80 Å. There are three inequivalent O sites. In the first O site, O(9) is bonded in a single-bond geometry to one Ni(1) atom. In the second O site, O(8) is bonded in a single-bond geometry to one Ni(1) atom. In the third O site, O(7) is bonded in a single-bond geometry to one Ni(1) atom. In the K4P6O19 framework, there are two inequivalent K sites. In the first K site, K(1) is bonded in a 8-coordinate geometry to two equivalent O(1), two equivalent O(3), two equivalent O(4), and two equivalent O(6) atoms. Both K(1)-O(1) bond lengths are 3.16 Å. Both K(1)-O(3) bond lengths are 2.82 Å. Both K(1)-O(4) bond lengths are 2.75 Å. Both K(1)-O(6) bond lengths are 2.80 Å. In the second K site, K(2) is bonded to one O(10), one O(3), two equivalent O(5), and two equivalent O(6) atoms to form KO6 octahedra that share  a cornercorner with one K(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and corners with four equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 46°. The K(2)-O(10) bond length is 2.86 Å. The K(2)-O(3) bond length is 2.81 Å. Both K(2)-O(5) bond lengths are 2.64 Å. Both K(2)-O(6) bond lengths are 2.82 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to one O(3), one O(4), and two equivalent O(1) atoms to form PO4 tetrahedra that share  a cornercorner with one K(2)O6 octahedra and corners with two equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 38°. The P(1)-O(3) bond length is 1.49 Å. The P(1)-O(4) bond length is 1.49 Å. Both P(1)-O(1) bond lengths are 1.65 Å. In the second P site, P(2) is bonded to one O(1), one O(2), one O(5), and one O(6) atom to form PO4 tetrahedra that share corners with two equivalent K(2)O6 octahedra,  a cornercorner with one P(1)O4 tetrahedra, and  a cornercorner with one P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles range from 45-62°. The P(2)-O(1) bond length is 1.63 Å. The P(2)-O(2) bond length is 1.62 Å. The P(2)-O(5) bond length is 1.50 Å. The P(2)-O(6) bond length is 1.50 Å. There are seven inequivalent O sites. In the first O site, O(10) is bonded in a distorted bent 120 degrees geometry to two equivalent K(2) atoms. In the second O site, O(1) is bonded in a bent 120 degrees geometry to one K(1), one P(1), and one P(2) atom. In the third O site, O(2) is bonded in a distorted bent 120 degrees geometry to two equivalent P(2) atoms. In the fourth O site, O(3) is bonded in a distorted single-bond geometry to one K(2), two equivalent K(1), and one P(1) atom. In the fifth O site, O(4) is bonded in a distorted single-bond geometry to two equivalent K(1) and one P(1) atom. In the sixth O site, O(5) is bonded in a distorted single-bond geometry to one K(2) and one P(2) atom. In the seventh O site, O(6) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one P(2) atom.