NaNp(HO2)2 crystallizes in the orthorhombic P2_12_12_1 space group. Na(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), and two equivalent O(1) atoms. Np(1) is bonded to one O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form a mixture of edge and corner-sharing NpO7 pentagonal bipyramids. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(4) atom. In the second H site, H(2) is bonded in a single-bond geometry to one O(2) atom. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Na(1) and one Np(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to one Na(1), two equivalent Np(1), and one H(2) atom. In the third O site, O(3) is bonded in a 1-coordinate geometry to one Na(1) and two equivalent Np(1) atoms. In the fourth O site, O(4) is bonded in a single-bond geometry to one Na(1), two equivalent Np(1), and one H(1) atom.
NaNp(HO2)2 crystallizes in the orthorhombic P2_12_12_1 space group. Na(1) is bonded in a 5-coordinate geometry to one O(2), one O(3), one O(4), and two equivalent O(1) atoms. The Na(1)-O(2) bond length is 2.44 Å. The Na(1)-O(3) bond length is 2.80 Å. The Na(1)-O(4) bond length is 2.51 Å. There is one shorter (2.32 Å) and one longer (2.37 Å) Na(1)-O(1) bond length. Np(1) is bonded to one O(1), two equivalent O(2), two equivalent O(3), and two equivalent O(4) atoms to form a mixture of edge and corner-sharing NpO7 pentagonal bipyramids. The Np(1)-O(1) bond length is 1.91 Å. There is one shorter (2.36 Å) and one longer (2.44 Å) Np(1)-O(2) bond length. There is one shorter (1.93 Å) and one longer (2.45 Å) Np(1)-O(3) bond length. There is one shorter (2.41 Å) and one longer (2.42 Å) Np(1)-O(4) bond length. There are two inequivalent H sites. In the first H site, H(1) is bonded in a single-bond geometry to one O(4) atom. The H(1)-O(4) bond length is 0.98 Å. In the second H site, H(2) is bonded in a single-bond geometry to one O(2) atom. The H(2)-O(2) bond length is 0.99 Å. There are four inequivalent O sites. In the first O site, O(1) is bonded in a distorted trigonal non-coplanar geometry to two equivalent Na(1) and one Np(1) atom. In the second O site, O(2) is bonded in a single-bond geometry to one Na(1), two equivalent Np(1), and one H(2) atom. In the third O site, O(3) is bonded in a 1-coordinate geometry to one Na(1) and two equivalent Np(1) atoms. In the fourth O site, O(4) is bonded in a single-bond geometry to one Na(1), two equivalent Np(1), and one H(1) atom.