Na2Np(CO4)2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(6), and one O(8) atom. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(6), and two equivalent O(8) atoms. Np(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and two equivalent O(7) atoms. There are two inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(3) and one O(4) atom. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one O(5) and one O(6) atom. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a distorted single-bond geometry to one Na(1), one Np(1), and one C(1) atom. In the second O site, O(5) is bonded in a distorted single-bond geometry to one Na(1), one Np(1), and one C(2) atom. In the third O site, O(6) is bonded in a distorted trigonal planar geometry to one Na(1), one Na(2), and one C(2) atom. In the fourth O site, O(7) is bonded in a water-like geometry to two equivalent Np(1) atoms. In the fifth O site, O(8) is bonded in a distorted water-like geometry to one Na(1) and two equivalent Na(2) atoms. In the sixth O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one Np(1) atom. In the seventh O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one Np(1) atom. In the eighth O site, O(3) is bonded in a distorted single-bond geometry to one Na(2), one Np(1), and one C(1) atom.
Na2Np(CO4)2 crystallizes in the monoclinic P2_1/c space group. There are two inequivalent Na sites. In the first Na site, Na(1) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(4), one O(5), one O(6), and one O(8) atom. The Na(1)-O(1) bond length is 2.46 Å. The Na(1)-O(2) bond length is 2.51 Å. The Na(1)-O(4) bond length is 2.66 Å. The Na(1)-O(5) bond length is 2.53 Å. The Na(1)-O(6) bond length is 2.39 Å. The Na(1)-O(8) bond length is 2.95 Å. In the second Na site, Na(2) is bonded in a 6-coordinate geometry to one O(1), one O(2), one O(3), one O(6), and two equivalent O(8) atoms. The Na(2)-O(1) bond length is 2.37 Å. The Na(2)-O(2) bond length is 2.37 Å. The Na(2)-O(3) bond length is 2.85 Å. The Na(2)-O(6) bond length is 2.30 Å. There is one shorter (2.27 Å) and one longer (2.28 Å) Na(2)-O(8) bond length. Np(1) is bonded in a 7-coordinate geometry to one O(1), one O(2), one O(3), one O(4), one O(5), and two equivalent O(7) atoms. The Np(1)-O(1) bond length is 1.84 Å. The Np(1)-O(2) bond length is 1.84 Å. The Np(1)-O(3) bond length is 2.45 Å. The Np(1)-O(4) bond length is 2.46 Å. The Np(1)-O(5) bond length is 2.61 Å. There is one shorter (2.03 Å) and one longer (2.20 Å) Np(1)-O(7) bond length. There are two inequivalent C sites. In the first C site, C(1) is bonded in a distorted bent 120 degrees geometry to one O(3) and one O(4) atom. The C(1)-O(3) bond length is 1.26 Å. The C(1)-O(4) bond length is 1.27 Å. In the second C site, C(2) is bonded in a distorted bent 120 degrees geometry to one O(5) and one O(6) atom. The C(2)-O(5) bond length is 1.28 Å. The C(2)-O(6) bond length is 1.25 Å. There are eight inequivalent O sites. In the first O site, O(4) is bonded in a distorted single-bond geometry to one Na(1), one Np(1), and one C(1) atom. In the second O site, O(5) is bonded in a distorted single-bond geometry to one Na(1), one Np(1), and one C(2) atom. In the third O site, O(6) is bonded in a distorted trigonal planar geometry to one Na(1), one Na(2), and one C(2) atom. In the fourth O site, O(7) is bonded in a water-like geometry to two equivalent Np(1) atoms. In the fifth O site, O(8) is bonded in a distorted water-like geometry to one Na(1) and two equivalent Na(2) atoms. In the sixth O site, O(1) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one Np(1) atom. In the seventh O site, O(2) is bonded in a 3-coordinate geometry to one Na(1), one Na(2), and one Np(1) atom. In the eighth O site, O(3) is bonded in a distorted single-bond geometry to one Na(2), one Np(1), and one C(1) atom.