KNiGa2P3(H2O7)2 crystallizes in the monoclinic C2/c space group. K(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. Ni(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent Ga(1)O5 trigonal bipyramids, and  an edgeedge with one P(1)O4 tetrahedra. Ga(1) is bonded to one O(1), one O(3), one O(5), one O(6), and one O(7) atom to form GaO5 trigonal bipyramids that share  a cornercorner with one Ni(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with three equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. There are two inequivalent P sites. In the first P site, P(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with four equivalent Ga(1)O5 trigonal bipyramids and  an edgeedge with one Ni(1)O6 octahedra. In the second P site, P(2) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra and corners with three equivalent Ga(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 51°. There are two inequivalent H sites. In the first H site, H(2) is bonded in a single-bond geometry to one O(4) atom. In the second H site, H(1) is bonded in a single-bond geometry to one O(4) atom. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a bent 120 degrees geometry to one Ga(1) and one P(2) atom. In the second O site, O(7) is bonded in a bent 150 degrees geometry to one Ga(1) and one P(2) atom. In the third O site, O(1) is bonded in a 2-coordinate geometry to one K(1), one Ga(1), and one P(1) atom. In the fourth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Ga(1) and one P(2) atom. In the fifth O site, O(2) is bonded in a 3-coordinate geometry to one K(1), one Ni(1), and one P(2) atom. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Ni(1), one Ga(1), and one P(1) atom. In the seventh O site, O(4) is bonded in a distorted water-like geometry to one K(1), one Ni(1), one H(1), and one H(2) atom.
KNiGa2P3(H2O7)2 crystallizes in the monoclinic C2/c space group. K(1) is bonded in a 6-coordinate geometry to two equivalent O(1), two equivalent O(2), and two equivalent O(4) atoms. Both K(1)-O(1) bond lengths are 3.09 Å. Both K(1)-O(2) bond lengths are 2.90 Å. Both K(1)-O(4) bond lengths are 3.07 Å. Ni(1) is bonded to two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form NiO6 octahedra that share corners with two equivalent P(2)O4 tetrahedra, corners with two equivalent Ga(1)O5 trigonal bipyramids, and  an edgeedge with one P(1)O4 tetrahedra. Both Ni(1)-O(2) bond lengths are 2.03 Å. Both Ni(1)-O(3) bond lengths are 2.14 Å. Both Ni(1)-O(4) bond lengths are 2.12 Å. Ga(1) is bonded to one O(1), one O(3), one O(5), one O(6), and one O(7) atom to form GaO5 trigonal bipyramids that share  a cornercorner with one Ni(1)O6 octahedra, corners with two equivalent P(1)O4 tetrahedra, and corners with three equivalent P(2)O4 tetrahedra. The corner-sharing octahedral tilt angles are 50°. The Ga(1)-O(1) bond length is 1.89 Å. The Ga(1)-O(3) bond length is 2.03 Å. The Ga(1)-O(5) bond length is 1.88 Å. The Ga(1)-O(6) bond length is 1.97 Å. The Ga(1)-O(7) bond length is 1.86 Å. There are two inequivalent P sites. In the first P site, P(1) is bonded to two equivalent O(1) and two equivalent O(3) atoms to form PO4 tetrahedra that share corners with four equivalent Ga(1)O5 trigonal bipyramids and  an edgeedge with one Ni(1)O6 octahedra. Both P(1)-O(1) bond lengths are 1.54 Å. Both P(1)-O(3) bond lengths are 1.56 Å. In the second P site, P(2) is bonded to one O(2), one O(5), one O(6), and one O(7) atom to form PO4 tetrahedra that share  a cornercorner with one Ni(1)O6 octahedra and corners with three equivalent Ga(1)O5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 51°. The P(2)-O(2) bond length is 1.53 Å. The P(2)-O(5) bond length is 1.58 Å. The P(2)-O(6) bond length is 1.56 Å. The P(2)-O(7) bond length is 1.56 Å. There are two inequivalent H sites. In the first H site, H(2) is bonded in a single-bond geometry to one O(4) atom. The H(2)-O(4) bond length is 0.98 Å. In the second H site, H(1) is bonded in a single-bond geometry to one O(4) atom. The H(1)-O(4) bond length is 0.99 Å. There are seven inequivalent O sites. In the first O site, O(6) is bonded in a bent 120 degrees geometry to one Ga(1) and one P(2) atom. In the second O site, O(7) is bonded in a bent 150 degrees geometry to one Ga(1) and one P(2) atom. In the third O site, O(1) is bonded in a 2-coordinate geometry to one K(1), one Ga(1), and one P(1) atom. In the fourth O site, O(5) is bonded in a distorted bent 120 degrees geometry to one Ga(1) and one P(2) atom. In the fifth O site, O(2) is bonded in a 3-coordinate geometry to one K(1), one Ni(1), and one P(2) atom. In the sixth O site, O(3) is bonded in a 3-coordinate geometry to one Ni(1), one Ga(1), and one P(1) atom. In the seventh O site, O(4) is bonded in a distorted water-like geometry to one K(1), one Ni(1), one H(1), and one H(2) atom.