K2Ni(NO3)4 crystallizes in the monoclinic Cc space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 11-coordinate geometry to one O(1), one O(10), one O(11), one O(5), one O(7), one O(8), one O(9), two equivalent O(12), and two equivalent O(2) atoms. In the second K site, K(2) is bonded in a 9-coordinate geometry to one O(1), one O(10), one O(11), one O(5), one O(6), one O(8), one O(9), and two equivalent O(3) atoms. Ni(1) is bonded in an octahedral geometry to one O(11), one O(2), one O(4), one O(6), one O(7), and one O(8) atom. There are four inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to one O(12), one O(4), and one O(7) atom. In the second N site, N(2) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(9) atom. In the third N site, N(3) is bonded in a trigonal planar geometry to one O(10), one O(5), and one O(6) atom. In the fourth N site, N(4) is bonded in a trigonal planar geometry to one O(11), one O(3), and one O(8) atom. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one N(2) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to two equivalent K(1), one Ni(1), and one N(2) atom. In the third O site, O(3) is bonded in a single-bond geometry to two equivalent K(2) and one N(4) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Ni(1) and one N(1) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one N(3) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one K(2), one Ni(1), and one N(3) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one K(1), one Ni(1), and one N(1) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one K(1), one K(2), one Ni(1), and one N(4) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one N(2) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one K(1), one K(2), and one N(3) atom. In the eleventh O site, O(11) is bonded in a 2-coordinate geometry to one K(1), one K(2), one Ni(1), and one N(4) atom. In the twelfth O site, O(12) is bonded in a distorted single-bond geometry to two equivalent K(1) and one N(1) atom.
K2Ni(NO3)4 crystallizes in the monoclinic Cc space group. There are two inequivalent K sites. In the first K site, K(1) is bonded in a 11-coordinate geometry to one O(1), one O(10), one O(11), one O(5), one O(7), one O(8), one O(9), two equivalent O(12), and two equivalent O(2) atoms. The K(1)-O(1) bond length is 3.24 Å. The K(1)-O(10) bond length is 2.79 Å. The K(1)-O(11) bond length is 3.12 Å. The K(1)-O(5) bond length is 3.28 Å. The K(1)-O(7) bond length is 2.83 Å. The K(1)-O(8) bond length is 3.33 Å. The K(1)-O(9) bond length is 3.02 Å. There is one shorter (2.86 Å) and one longer (3.33 Å) K(1)-O(12) bond length. There is one shorter (2.93 Å) and one longer (3.33 Å) K(1)-O(2) bond length. In the second K site, K(2) is bonded in a 9-coordinate geometry to one O(1), one O(10), one O(11), one O(5), one O(6), one O(8), one O(9), and two equivalent O(3) atoms. The K(2)-O(1) bond length is 2.86 Å. The K(2)-O(10) bond length is 2.77 Å. The K(2)-O(11) bond length is 2.98 Å. The K(2)-O(5) bond length is 2.98 Å. The K(2)-O(6) bond length is 3.21 Å. The K(2)-O(8) bond length is 2.92 Å. The K(2)-O(9) bond length is 2.87 Å. There is one shorter (2.91 Å) and one longer (2.98 Å) K(2)-O(3) bond length. Ni(1) is bonded in an octahedral geometry to one O(11), one O(2), one O(4), one O(6), one O(7), and one O(8) atom. The Ni(1)-O(11) bond length is 2.16 Å. The Ni(1)-O(2) bond length is 2.08 Å. The Ni(1)-O(4) bond length is 2.08 Å. The Ni(1)-O(6) bond length is 2.09 Å. The Ni(1)-O(7) bond length is 2.08 Å. The Ni(1)-O(8) bond length is 2.10 Å. There are four inequivalent N sites. In the first N site, N(1) is bonded in a trigonal planar geometry to one O(12), one O(4), and one O(7) atom. The N(1)-O(12) bond length is 1.24 Å. The N(1)-O(4) bond length is 1.27 Å. The N(1)-O(7) bond length is 1.29 Å. In the second N site, N(2) is bonded in a trigonal planar geometry to one O(1), one O(2), and one O(9) atom. The N(2)-O(1) bond length is 1.25 Å. The N(2)-O(2) bond length is 1.31 Å. The N(2)-O(9) bond length is 1.25 Å. In the third N site, N(3) is bonded in a trigonal planar geometry to one O(10), one O(5), and one O(6) atom. The N(3)-O(10) bond length is 1.26 Å. The N(3)-O(5) bond length is 1.25 Å. The N(3)-O(6) bond length is 1.29 Å. In the fourth N site, N(4) is bonded in a trigonal planar geometry to one O(11), one O(3), and one O(8) atom. The N(4)-O(11) bond length is 1.28 Å. The N(4)-O(3) bond length is 1.23 Å. The N(4)-O(8) bond length is 1.29 Å. There are twelve inequivalent O sites. In the first O site, O(1) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one N(2) atom. In the second O site, O(2) is bonded in a distorted bent 120 degrees geometry to two equivalent K(1), one Ni(1), and one N(2) atom. In the third O site, O(3) is bonded in a single-bond geometry to two equivalent K(2) and one N(4) atom. In the fourth O site, O(4) is bonded in a bent 120 degrees geometry to one Ni(1) and one N(1) atom. In the fifth O site, O(5) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one N(3) atom. In the sixth O site, O(6) is bonded in a distorted bent 120 degrees geometry to one K(2), one Ni(1), and one N(3) atom. In the seventh O site, O(7) is bonded in a distorted trigonal planar geometry to one K(1), one Ni(1), and one N(1) atom. In the eighth O site, O(8) is bonded in a 2-coordinate geometry to one K(1), one K(2), one Ni(1), and one N(4) atom. In the ninth O site, O(9) is bonded in a distorted single-bond geometry to one K(1), one K(2), and one N(2) atom. In the tenth O site, O(10) is bonded in a 3-coordinate geometry to one K(1), one K(2), and one N(3) atom. In the eleventh O site, O(11) is bonded in a 2-coordinate geometry to one K(1), one K(2), one Ni(1), and one N(4) atom. In the twelfth O site, O(12) is bonded in a distorted single-bond geometry to two equivalent K(1) and one N(1) atom.